@@david.ricardo You never know if that's the case, dude can possibly be the next bill gates. Don't go judging people around for what their not good at.
Thank you so much, you saved me! This is the ONLY video that actually explains everything step-by-step without assuming that students know something when they actually don't. Very clear and easy to understand, thanks!
I am n Calculus and I had to go back to these quadratics because once one gets into this higher level of math he/she still has to go back to these simple problem. I had forgot about these quadratics that continuously keeps coming back. Thank You for helping me, I understand the concept both ways completely.
I'm a little late but basically you take the product of the first and last terms and find their factors. Then you chose factors that when added or subtracted equal to the middle term. Then you make pairs of two and then take out commons and the stuff in both brackets should be the same. Then you delete one of the brackets and then put the stuff outside the brackets together into a bracket and your done. I suggest watching some more videos as I am absolute garbage at explaining things
@@vardag3196 wow thanks man, definitely haven't dropped out of college since this comment was made. Definitely a relevant comment to make. Big ups friend.
@@TheWiery322 I don't know if that was sarcastic or not. If it wasn't your welcome. If it is, dude I just got in grade 9 and I am just starting to learn this. You should never have dropped out of college. Stop being salty at a minor who was trying to help you yet you are taking out your anger at him.
He explains it wayy better than my teacher. He makes it easier but isnt quadractic formula the same? I know how to do that but this I still dont understand.
If people don’t know what’s happening: s^2 - 2s - 35 = 0 Let’s say it like this. a + b = -2 and ab = -35 This means either a or b will be negative. But how do we find out. Simple, list out the factors of 35. The unique combo is 5 and -7. 5 + (-7) is -3and 5 x (-7) is 35. So we have this equation. s^2 +5s - 7s -35. Now what now. I like to put these into pairs and figure out what common factor they have, aka. factoring. So s^2 and 5s have a common factor of s so we get this. s(s+5) We can do the same thing to -7s - 35 using (-7) so we get -7(s+5) So we get this: s(s+5) - 7(s+5) Because we already have the factor of s + 5, we don’t need it, so we remove this, get the two numbers outside the parenthesis and make that a factor: (s + 5)(s - 7) Now let’s make it so these expressions equal zero. -5 and 7. These are our solutions for s. We can double check this as well. 49 (7 squared) - 14 (-2 x 7) - 35 = 0 25 (-5 squared) + 10 (-2 x -5) - 35 = 0
سبحان الله وبحمده سبحان الله العظيم استغفر الله العظيم الذي لا إله إلا هو الحي القيوم و أتوب إليه سبحان الله وبحمده عدد خلقه ورضا نفسه وزنة عرشه ومداد كلماته اللهم صَلِّ وسَلّمْ عَلَى نَبِيْنَا مُحَمد ﷺ
Back in 1980s when I was in junior high, one of my math teachers in China taught us below formula to solve any quadratic equations ax^2 + bx + c = 0, then we have (-b/(2a) - u)(-b/(2a) + u) = c/a, then we have (u + b/(2a))(u - b/(2a)) = -c/a. Solve the u we will get x = -b/(2a) - u or x = -b/(2a) + u.
gotta love it when your algebra 1 teacher was a terrible teacher so you barely know the basics so you gotta watch all these videos to have a clue of what to do :). Thanks khan academy
tastyyy and nutritious math thanks khan academy! I donated my past exams but will donate again soon. Your clear voice and explanation really makes me love math.
use this formula, it works for any quadratic, -b plus or minus root b^2-4ac/2a were a+b+c=0 i get 9+-root 81-144/4. which esentially simplifies to 9+-root-63/4 however you cant root a negative number unless you use the term j for all you electrical engineers which is equal to root -1.
I’m 22 years old and still don’t know this by heart. And I consider myself math minded. I get tripped up trying to figure out how to factor when the leading coefficient of x^2 is not 1. The guessing game is the most difficult part for me at that point, I know there’s a shortcut but I don’t know it well enough to whip it out at anytime.
ax^2+bx+c=0. Find 2 numbers adding to b and multiplying to (a * c). Call those two numbers r & s. Then set up bx = rx + sx so that you have ax^2+rx+sx+c=0. Then you factor by grouping.
Quadratics is so counter-intuitive, it's a real pain-in-the-ass to learn. Despite that, I think I understand this part of it to a useful extent thanks to you. Your videos sure beat trying to read my illegible notes.
At that point in the problem where you've factored the equation and got a common factor from both groups, you need to further factor out the common factor. In this case the (s+5). As Rotten Potato said, the factors(numbers and/or variables) left outside the parenthesis put those together in their own parenthesis. You end up with a equation times and equation "(a + b)(x - z)". In this quadratic equation we're equaling to zero, so take both equations out of their parenthesis and put "= 0" on both. Solve the simple equations for your answer(s)
No clue either. I could be wrong but the way I see it, is like this: There are two terms that are the same in the formula s(s+5)-7(s+5) See how we have the s and the -7 outside of brackets? My theory is that for whatever reason, one of the (s+5) terms can be eliminated and replaced with the s and -7 combined, to make (s-7) So you have the s(s+5)-7(s+5), remove one of the s+5, replace it with the terms outside the brackets, and make that into a bracket. I could be entirely wrong so please take this with a pinch of salt, but this is how I interpret it
So in this case the variable (s) equals the inverses of the two numbers you initially used in factoring out? Couldn’t you do this with other equations? Cause if so that’s a major short cut.
This is probably too late to help you with your homework, but if you consider the question as 49t^2 + 147t-1372 you can simplify the problem to 49 (x^2 + 3 x - 28). Then solve from there the part within brackets which should get you on your way to the answer. Good luck.
Rayshonda Hedgeh hey He took common or find similar numbers in the equation above. He took s common from s² + 5s which is s(s + 5). Then took 7 common from 7s-35 Here 35 is divisible by 7 by 5 times so 7(s + 5) And then here we need two values for s first we take s+5 and then s-7
So, if you didn't do the factoring by grouping, first, how do you get the numbers for the straight factoring method? It seems like that would have to be a -guess and check situation- which could take almost as long as the grouping method? Am I wrong? Please, correct if I am, because I want to better understand.
@@cefb8923 / The point of these longer methods is to help with understanding why the method works. It is asking you to know the logic behind each step to make it easier to remember and apply to other problems. The old system showed the quickest way to do it, and wanted you to memorize each step of the process. I don’t yet know if the new way is better or worse.
how would this even work for (5x^2 - 6x + 1). In this case. a + b = -6, while a.b is equal to 1. so it be (-5)+(-1)= -6 however, (-5).(-1) would not equal to 1.Even if i were to use other numbers it will not fulfill both requirements, so please correct me here what am i doing wrong using ur specific solution.
yea im still a little confused, how did u get the 7 alone?. sorry math is very troubling for me, ever since i was a kid i had trouble comprehending math, and obviously it still carries on.
cleared everything up in less than 5 minutes for me. i would be lost without this man
YOU MADE IT SO COMPLICATED IT WAS SUPPOSED TO BE REAL SIMPLE
yna how????
Because he really wants you to understand math not just solve equation without knowing what you are doing like a robot
@@david.ricardo fair enough but i just wanna pass
@@david.ricardo chillllllllll mate
@@david.ricardo You never know if that's the case, dude can possibly be the next bill gates. Don't go judging people around for what their not good at.
Thank you so much, you saved me! This is the ONLY video that actually explains everything step-by-step without assuming that students know something when they actually don't. Very clear and easy to understand, thanks!
Thank you so much! Thanks! In my head, It feels like someone walked insinde a dark room and just turned on the lights.
Dork
Its almost poetic
@@preparator9925 facts
It took me a few days, but I think I'm starting to get this. I can't wait to pass the math part of my GED, it's the only subject holding me back.
About to try and get my GED, really scared of the math portion
insaneshadow85 Same here! I'm terrified!! D:
So
Did you?
We need to know
Did you do it?
guess i'll just die.
its been 3 years are you dead
Yeah same
@@shoaibkhan-qx3oq only on the inside.
@@sevenisacannibal still?
@@youtubeenjoyer5083i am
i don't understand my teacher. i don't understand this also. i think it's time to plant in backyard with potatoes.
It’s been 2 years did they grow?
@@universalyoutuber195 lmao
@@universalyoutuber195 omg idk why I said this HAHHAHAHHA. maybe I'm the potato 😭
it's been 5 years how much did you earn by your potatoes?
I am n Calculus and I had to go back to these quadratics because once one gets into this higher level of math he/she still has to go back to these simple problem. I had forgot about these quadratics that continuously keeps coming back. Thank You for helping me, I understand the concept both ways completely.
Nope, I still have no clue what's going on
ua-cam.com/video/X7B_tH4O-_s/v-deo.html this helped me to understand this video
Lauren Bethune are you dumb?
Vic Wang apparently
Lauren Bethune what do you mean apparently
Vic Wang I mean, according to you I must be right, since you think it's so odd that I didn't understand this concept?
God bless you.
Got an A on my test.
I love Khan Academy. I would be failing college algebra without them.
I like how your name is just Rob.
Rob this is for highschool though
Rob this is grade 9 class algebra
@@meooorw8801 You still need to understand algebra concepts for calculus though
@@LucasAlves-hi2kx ye sorry
Oh mathematics! I forgot how rewarding you are after the subject is mastered. I get a big smile on my face when I solve these problems.
im completely lost
i have no idea whats happening
I'm a little late but basically you take the product of the first and last terms and find their factors. Then you chose factors that when added or subtracted equal to the middle term. Then you make pairs of two and then take out commons and the stuff in both brackets should be the same. Then you delete one of the brackets and then put the stuff outside the brackets together into a bracket and your done. I suggest watching some more videos as I am absolute garbage at explaining things
@@vardag3196 wow thanks man, definitely haven't dropped out of college since this comment was made. Definitely a relevant comment to make. Big ups friend.
@@TheWiery322 I don't know if that was sarcastic or not. If it wasn't your welcome. If it is, dude I just got in grade 9 and I am just starting to learn this. You should never have dropped out of college. Stop being salty at a minor who was trying to help you yet you are taking out your anger at him.
@@vardag3196 bro I wasn't mad. It was complete sarcasm. Sorry if it came across wrong. And I did'nt know you were a minor. My apologies
THANK GOD FOR THIS VIDEO
He explains it wayy better than my teacher. He makes it easier but isnt quadractic formula the same? I know how to do that but this I still dont understand.
Tanks a lot
It really helps though it is complicated at first
How to solve mathematics:
Step 1: Write the equation
Step 2: Cry your eyes out
Exactly
Yep
Who else is here for an assignment?
Yep
Yessir
Mhm
yes unfortunately.......... :(
If people don’t know what’s happening:
s^2 - 2s - 35 = 0
Let’s say it like this.
a + b = -2 and ab = -35
This means either a or b will be negative.
But how do we find out. Simple, list out the factors of 35.
The unique combo is 5 and -7. 5 + (-7) is -3and 5 x (-7) is 35.
So we have this equation.
s^2 +5s - 7s -35.
Now what now. I like to put these into pairs and figure out what common factor they have, aka. factoring.
So s^2 and 5s have a common factor of s so we get this.
s(s+5)
We can do the same thing to -7s - 35 using (-7) so we get -7(s+5)
So we get this: s(s+5) - 7(s+5)
Because we already have the factor of s + 5, we don’t need it, so we remove this, get the two numbers outside the parenthesis and make that a factor:
(s + 5)(s - 7)
Now let’s make it so these expressions equal zero.
-5 and 7. These are our solutions for s.
We can double check this as well.
49 (7 squared) - 14 (-2 x 7) - 35 = 0
25 (-5 squared) + 10 (-2 x -5) - 35 = 0
سبحان الله وبحمده سبحان الله العظيم
استغفر الله العظيم الذي لا إله إلا هو الحي القيوم و أتوب إليه
سبحان الله وبحمده عدد خلقه ورضا نفسه وزنة عرشه ومداد كلماته
اللهم صَلِّ وسَلّمْ عَلَى نَبِيْنَا مُحَمد ﷺ
Back in 1980s when I was in junior high, one of my math teachers in China taught us below formula to solve any quadratic equations ax^2 + bx + c = 0, then we have (-b/(2a) - u)(-b/(2a) + u) = c/a, then we have (u + b/(2a))(u - b/(2a)) = -c/a. Solve the u we will get x = -b/(2a) - u or x = -b/(2a) + u.
Thanks so much, I have an Algebra final tomorrow and I needed to get a few things cleared up in my head! :)
You're lucky to have remembered those things long ago
gotta love it when your algebra 1 teacher was a terrible teacher so you barely know the basics so you gotta watch all these videos to have a clue of what to do :).
Thanks khan academy
Same
tastyyy and nutritious math thanks khan academy! I donated my past exams but will donate again soon. Your clear voice and explanation really makes me love math.
amazing how math never really changes
OMG this actually helps, I was so confused about this one, THANKS!
I am a pre-middle schooler learning ahead of curriculum, this really helped
How are you doing now?
@@Epic24123 i'm doing well! wow, it's been a few years, I forgot I even commented this :)
This Video is way better than my teacher Thank you
i totally understand my whole factoring projet for Algebra II now. thank you soooo much.
use this formula, it works for any quadratic, -b plus or minus root b^2-4ac/2a were a+b+c=0 i get 9+-root 81-144/4. which esentially simplifies to 9+-root-63/4 however you cant root a negative number unless you use the term j for all you electrical engineers which is equal to root -1.
Extremely helpful.
Teacher had me confused all day.
I’m 22 years old and still don’t know this by heart. And I consider myself math minded. I get tripped up trying to figure out how to factor when the leading coefficient of x^2 is not 1. The guessing game is the most difficult part for me at that point, I know there’s a shortcut but I don’t know it well enough to whip it out at anytime.
ax^2+bx+c=0. Find 2 numbers adding to b and multiplying to (a * c). Call those two numbers r & s. Then set up bx = rx + sx so that you have
ax^2+rx+sx+c=0. Then you factor by grouping.
When factored, 2x^2- 9x- 18 ends up being (2x + 3)(x - 6) using Khan's factoring method. From there, you can deduce that X=6 and X= -1.5
Your really good at teaching this!!
Quadratics is so counter-intuitive, it's a real pain-in-the-ass to learn. Despite that, I think I understand this part of it to a useful extent thanks to you. Your videos sure beat trying to read my illegible notes.
Thank you, great resource, just solved my problem
I was watching this while my tutorBeas watching me and didn't say anything u did a better job than them
This video helped make me understand a little
As a grade 4 student, thanks for finally clarifying everything to me !
YOU’RE LEARNING THIS IN THE FOURTH GRADE??
i have a question. why is it suppose to be a+b=0 & a•b=0? is this a rule? does it work with every question?
Xing AoShen He begins to explain at 4:39.
yes its a rule
Instructions not clear enough. Got my slong stuck in a toaster
My personal recommendation to fixing your problem,
Slong = Toaster
Thank you VERY VERY much for your videos.
Thank you so much, i understand it a little better now lol
So you have to see what A and B must be? What if the problem is more complex and doesn't give such an easy answer.
Great Video! Makes Sense!
Nice video.
Thanks for this tutorial!!!!!!!!!!
@PeterZ3000 Now I get it. Had to watch "Factor by Grouping and Factoring Completely" to understand better.
Thanks man ur a big help.
Thank you soooooo muuuuch
👍🏿✅ 💯💯.
Sincerely, Justin Maduako
helps so much
i love your stuff g
How to solve this quadractic equation:
(a-b)x^2-(a+b)x+2b=0.
Anyone help please..
i have a test tmrw u saved my life
tytyty
How did you do? I have a final in a few days I am studying for
Thank you so much, this really helped me with my math test, this and other videos have been helping me through school
Very helpful thanks!
Solve the following quadratic equation for x :
x^2 + (a/a+b+a+b/a)x + 1
Bless you for this, I was stuck on a really easy part and now I understand! Thank you, thank you!!
Set❤️
Thanks pal :)
thanks
In India we say it as, The Splitting middle term method!!
Some topics in mathematics just make me so sad...
Parallel lines, for example. They have so much in common, but they’ll never meet!
you get me real good man reall funni man yes yes cool
2:22 CAN SOMEONE EXPLAIN THIS TO ME!!! How do go from *s(s+5)-7(s+5)* to *(s+5)(s-7)* ??
you combine the both the (s + 5) into one. you then just connect s and -7 to form (s - 7) put them together and it becomes (s + 5)(s - 7)
At that point in the problem where you've factored the equation and got a common factor from both groups, you need to further factor out the common factor. In this case the (s+5). As Rotten Potato said, the factors(numbers and/or variables) left outside the parenthesis put those together in their own parenthesis. You end up with a equation times and equation "(a + b)(x - z)".
In this quadratic equation we're equaling to zero, so take both equations out of their parenthesis and put "= 0" on both. Solve the simple equations for your answer(s)
Rotten Potato what does that mean?????
Basically you can’t have two same values so convert the second value into the number being multiplied with the second value
I just got out of 7th grade and am studying this for next year. I don't like how difficult this is.
made this to complicated it is a easier way to explain this without doing all those extra steps
That "s" and 5 made it hard to follow at times, for me.
Easy fun stuff
2:35 is where I have no clue why this is supposed to work
No clue either. I could be wrong but the way I see it, is like this:
There are two terms that are the same in the formula s(s+5)-7(s+5)
See how we have the s and the -7 outside of brackets?
My theory is that for whatever reason, one of the (s+5) terms can be eliminated and replaced with the s and -7 combined, to make (s-7)
So you have the s(s+5)-7(s+5), remove one of the s+5, replace it with the terms outside the brackets, and make that into a bracket.
I could be entirely wrong so please take this with a pinch of salt, but this is how I interpret it
It would be a lot simpler just to use the shortcut. :/ But maybe that complicated way will be of use in the future. Who knows?
So in this case the variable (s) equals the inverses of the two numbers you initially used in factoring out? Couldn’t you do this with other equations? Cause if so that’s a major short cut.
Yeah I agree I have been struggling on this math so badly that I didn't get what it meant?
Are there any videos where he uses the actual quadratic equation because this is much harder than just using the actual quadratic equation.
Yall im bouta take a test on this wish me luck
Still have no idea what to do
How was the test
as soon as possible
How do I solve 4.9t squared + 14.7t - 137.2 = 0
This is probably too late to help you with your homework, but if you consider the question as 49t^2 + 147t-1372 you can simplify the problem to 49 (x^2 + 3 x - 28). Then solve from there the part within brackets which should get you on your way to the answer. Good luck.
Thank you for the helpful video. This really helped me get a grasp on the concept! :)
How the hell did he get from -7(s+5) to (s-7) by multiplying by s at around 2:40?????????????
Rayshonda Hedgeh hey
He took common or find similar numbers in the equation above.
He took s common from s² + 5s which is s(s + 5).
Then took 7 common from 7s-35
Here 35 is divisible by 7 by 5 times so 7(s + 5)
And then here we need two values for s first we take s+5 and then s-7
So, if you didn't do the factoring by grouping, first, how do you get the numbers for the straight factoring method? It seems like that would have to be a -guess and check situation- which could take almost as long as the grouping method? Am I wrong? Please, correct if I am, because I want to better understand.
it's very complicated😕
I can't get though this without sleeping. I hate math T.T
slow down and explain each step more please.
2:03 how does it become (s+5) instead of becoming (s-5)??
U can't get -35 if u use s-5 cuz the answer will be +35. In multiplication, same sign is + and diff sign is - ( no matter what sign they have)
Why we cant solve quadratic equations with traditional methods?
This is what I really hate about learning math, there is never explanation of WHY were doing any of it. Why can't you solve it the traditional way?
@@cefb8923 same
@@cefb8923 / The point of these longer methods is to help with understanding why the method works. It is asking you to know the logic behind each step to make it easier to remember and apply to other problems. The old system showed the quickest way to do it, and wanted you to memorize each step of the process. I don’t yet know if the new way is better or worse.
That just confused me even more... less is more Khan!
Khan wants you to actually understand what you are doing not just do some steps.
how would this even work for (5x^2 - 6x + 1).
In this case. a + b = -6, while a.b is equal to 1.
so it be (-5)+(-1)= -6
however,
(-5).(-1) would not equal to 1.Even if i were to use other numbers it will not fulfill both requirements, so please correct me here what am i doing wrong using ur specific solution.
do you use a slate when you write?
how to use factoring method for equations when coefficient of x^2 is not 1....e.g. 3x^2-10x+3=0
I learned this so differently in college. Probably because this was in 1993.
People are doing this for college tests yet i am doing only for a year 8 test
He lost me at "undistribute". :-(
Otherwise, I love the videos.
Same here.
Isn't it easier to do the quadratic formula??
Ya
yea im still a little confused, how did u get the 7 alone?. sorry math is very troubling for me, ever since i was a kid i had trouble comprehending math, and obviously it still carries on.
The thing is that a is 6, except that I'm good but I can't do this
Everything kind of made sense until 2:24.. then suddenly it made no sense to me.
It took me 2min looking at an answer sheet to understand this
@Everyone cant we just use asterisks method to do this?
i understand that -35 is the same thing as 5*-7 but how in the hell does he just eliminate a giant factor of the problem. it just goes to dust