Solving simultaneous equations by substitution
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- Опубліковано 29 жов 2019
- Now we look at solving simultaneous equations by a method of substitution. This involves re-arranging one equation to isolate a variable and then substituting this into the other equation.
Exam tomorrow and i still dont know how to do them
Thank you so much for the explanation. This was a really difficult concept for me to understand. Thank u again for a great explanation 😀
.
Even for me
@@JardeOri-kc8ov what do you mean even for me? You think you’re Jimmy neutron? 😂
Me too, I get it now
BRO'S LAUGH STUNNED MY HEART, NEVER LEAVING MATHS SIDE AGAIN
Ahhh, that just clarified all my confusions! Thanks alot for this, this video was really helpful🤧✨
This method was surprisingly easier than what my teacher taught me 💀
The teachers are always giving hard methods
No really though
Cause teachers are shit 😂
Exactly
@@arthurmarston7128theyre just shit at teaching
Thank you so much!!! This was so helpful!! 💕💫
Thank your for this short and concise video. Definitely leaving a like
There is however a different solution to x+3y and 4x-7y.To make x the subject of the formulae of the first equation we get x=11-3y.Therefor when substituting x into the second equation we get 4(11-3y)-7y=6.After that we multiply everything in the bracket with 4.So after multiplying we get 44-12y-7y=6.We then group like terms which require transposing so after grouping like terms we get -12y-7y=6-44.After simplifying this equation we get -19y=-38.We then divide by 19 at both sides so 19y divided by 19y will answer with y.-38 divided by 19 gives us -2.So y=-2.To find x we substitute y in the first equation and therefor x+3(-2)=11.We then simplify the equation which will be x+-6=11.We then transpose the 6 to the 11 to group like terms.So then x=11+6 (The sign of the transposed value turns into the opposite sign.).So then x=17.To test if we are correct use any of the equations like x=3y=11.Simplify in the expression we get 17+3(-2)=11.However both answers are correct.
;-;
Yeah you are correct
y is not -2, -19y=-38, so -y=-2 and y=2, and you got rid of the minus on the left, but not on the right, which you can't do, you need to un-minus both sodes
@@RayansCompilationno the video was right
Thanks a lot bro! It really helped a lot... Keep up the Great Work!
Thank you so much for this explanation it has being a very difficult topic for me to understand again thank you
Never understood this method and my finals are close by!! Thankyou grabbed your explanation in secondss
Thank you Sir,
Everything well explained!!
You made things very easy for me
Thank you so much 🥰💘 this topic is very hard to understand.But now I understand
Thank you soo much you saved my day because tomorrow is my exam and my concept wasn't clear but you saved my dayyy
Did you pass?
Thank you! Keep up the good work 🙂
Still can't get it...
Your cooked bro
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@@DakotaPeters-kp9uxfr (I can’t do them either)
You and me both 😢
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You my friend are the goat I can't tell you how useful this was much love❤
Bro thank you bro I was having trouble how to do it as a grade 7 student and I get it after this video thank you so much after a very long time I finnally get it.❤❤
Thank you so much you the best teacher ever.
Thank you very much.Your explanations are quite clear and easy to understand.
I have learned nothing the words on the screen is hiding the equation and I'm not see the whole equation
Thank you so much. The reason I'm only really good at sciences (including comp sci) is because I only remember to do things if I know why. I couldn't remember anything about differentiation by first principles if I didn't know what we were trying to achieve, and just as such you have explained *why* we do what we do
tyssmmm, ive a maths test tomorrow and ngl this vid really helped
Waw you are such a good teacher thanks man
Wont y become negative 2 cause positive 44 got switched to the other side so 6 minus negative 44 equals to negative 38 so help
No because sir didn't switch 44 he switched -12y and -7y
how is -12y-7y = positive 19? shouldnt it equal -19? But even without the negative next to the 12y it would be positive 5. or maybe 12y minus negative 7y, which does equal +19?
when u mnus with a negative it becomes bigger
Like, it's wrong
when you put a number from one side of an equals (=) sign to the other .. you change it from positive to negative. or negative to positive.
Exactly
-×-=+
Thanks you ,you so great at teaching I understand everything 😂
Thank you so much for helping me.
I understand better now..
Thanks! Needed a quick recap, and this provided.
Thank youu man this help me so much and I can't believe I actually understood it :-O
Tomorrow is my paper thank you soon much I understood the question
Thank you for the explanation I appreciate it and l really do understand everything thank you
Thank you very much for the wonderful explanation😔🙏🙏
Thanks this is so easy and understandable ❤
thanks the way you explained it know i understand
Thank you so much😊🥺💯. This is my weak area in maths and I can now do it better😊🙏
Love the handwriting!
Which class do you learn this
You know what you teach math very well.bro full support to you thank you so much
ur voice makes me melt ❤️🔥
brilliant explaining bro❤
A much better and faster method of doing this. Mucho Gracias
Thanks a lot this tutorial works
I have a Question? When you isolate the variable Y in the first equation why do you change sign in 7,in third equation apear -7 and sevent stay in same side of iquality.i don't know that.If you do that I have to do that.i didn't know that .thankyou
You can break it down into smaller steps. You could subtract 3x and make it -y=7-3x and then if you flip the signs it becomes y=-7+3x which we write the other way round as y=3x-7
Can’t you plug Y=2 into the first line making it become 6 and then make 6 go to the other side and make it negative 6 and then subtract eleven w -6 to get 5??
Where did you get this 7y
Thank you today is my math exam and now I understand how to solve it thx
that was easy for the first time willing to see the next one in I think it will be a difficult one if there is
Thank you so much may God bless you 🙏
thanks man my teacher tried to explain it to me in every way but i still wouldn't get it thank you:)
You earned a new subscriber
Thanks a lot! 👍😀👌
what if the coefficient is not one but 2 or three?
Then just simplify it
"2x=11-3y"
divide bothsides by 2
x= 5.5-1.5y
(THIS IS MY MADE UP EXAMPLE THXS)
edit;
"2y=3x-7"
divide both sides
y=1.5x-3.5
so yh
(THIS IS MY MADE UP EXAMPLE THXS SO DONT USE TO SOLVE THIS EXACT EQUATION THX LUVS)
very helpful for me , tqsm 🙏
Thanks This Helped :)
this was sooo helpful😍
How 3 comes after re arranging equation number1.
YOU HAVE A BIG FUTURE
Thank you so much 😻❤️❤️
When I was in class, my brain was in loops of multiverses
Thanks, it does help.
Is this working for other people because I'm still helps confused
How did sir get 38
12y+7y =19y
44-6=38
38÷19 = 2
Ig
How did the 9 came
Thanks for making it easier🎉
im confused how did he get 19x-19 where did the 19 come from
Please do you use this method only when there is a variable with a coefficient of 1?🤔🤔
You can do it in any situation, but it might not be the easiest in other circumstances
He teaches better than my techer with 15 years experience
I can't understand sir, can u help me?
Love your voice, love your explanation. Thanks so much!!
Thanks you're a life saver
Thanks you brother ❤
U r awesome bro
Easy solve by substitution.
Original New equation
X + 3y = 11. -4x-12y = -44
4x - 7y = 6. 4x- 7y = 6
Mult top row by -4
--------------
- 19y= -38 Divide both sides by -19
Now y = 2.
Plug in 2 for y and ….
X+ 3(2) = 11
X + 6 = 11 -> subt 6 from both sides leaving X = 5
Plug x= 5 and y = 2 into both original equations as proof
Nice
Ty bro cause i was tweaking in class
Thanks 👍 for making me understand 😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉
Thank you sir so much 😊😊
Thank You!
why does 4 become 44?
4 times 11 is 44
Thank you so much sir
On equations 2 isn't y=3x+7
Y===3X+7=
3X=7-y=
3X=6
X=2
6++7==13==(y)
I still don't understand how you workout equation 2
omggg i loveee youu thank you so much! also ur voice is amzaing!
thank you sir am very greateful
thank you dude
Nice guide
3:37 why didn’t you rearrange equation 3 the same way you arranged it in the first example, just curious
i was wondering the same thinf
Because then it wouldn't work. Using equation II, we have solved the value of x. Later on, the equation we had rearranged will have to be used. We put the value of x in the re-arranged equation I and we get the value of y. Hope this helped!
Hi,
how did u get 19x 4:24
you added 10x by 9x
Thx@@dragon_a9yo651
Thanks alot , your voice is very reassuring
Why did 4 become 44?
4 got multiplied by 11
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I looooovvvvvveeeee this video 😊
The way you explained everything step by step is excellently easier and better than what my teachers have ever explained 😊❤
👍keep up the good work 👍👍
How did u get 44
This multiply by 11×4
Actual lifesaver
I honestly find elimination way easier
I think i just didnt understand or listen when my teacher talked about substitution
Thank you
Please I don't understand.
Please explain number 2 .
love it made it so much clearer now thanks LOVE IT!!!!!!
thank you !!!!!!!!!
Please help me solve (2x-y) =1 and 6x +7y= 2
So we can rearrange the first one to make it -y=-2x+1 and then flip the signs to make it y=2x-1. We can then substitute this into the second one so you have 6x+7(2x-1)=2. Expand the brackets and we get 6x+14x-7=2. Add 7 and combine the X terms and it becomes 20x=9 divide by 20 and x=9/20 which is 0.45. Substitute that into any of other equations (y=2x-1 is the easiest, but the others will work too) and then, you get x=2×(9/20)-1 which is (18/20)-1 which means x=-2/20 which is -1/10 or -0.1