I've seen this trick very often on YT in the last months. really no one uses a very easy method to solve such an equation of third degree after multiplying the equation with -1 we receive: x³ - x² + 80 = 0 by inspection we found, that one solution is x = -4 Therefore x³ - x² + 80 = (x+4)(x² + ax + 20) the variable a can be found by comparing left and right side by writing the right side without the brackets
you had the answer at 1 minute 20 seconds. X =-4 -4 times -4 =16. -4 times -4 times -4 = -64. 16 - (-64) =80 (not easy to type out clearly) He was just fitting in numbers to make it work, like @robertloveless4938 said. After all -15 plus -65 also equals -80 but that doesn't work in the equation. You either have to guess -4 or just keep trying numbers until it works.
I cheated. I immediately knew x had to be negative, then I plugged in numbers, starting with -3 (answer =36), and worked the numbers. . Fortunately, I didn't have to go past 4.
You cheated no more than "Learncommunolizer did ! He had to know that X equaled -4 to plug in his equation at the 1:20 ish point. But YES, it was clear it had to be negative.
I've seen this trick very often on YT in the last months.
really no one uses a very easy method to solve such an equation of third degree
after multiplying the equation with -1 we receive: x³ - x² + 80 = 0
by inspection we found, that one solution is x = -4
Therefore x³ - x² + 80 = (x+4)(x² + ax + 20)
the variable a can be found by comparing left and right side by writing the right side without the brackets
You don't justify breaking 80 into 16 and 64. Why not 50 and 30.
Using the answer we could guess is not math
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5√4+y
you had the answer at 1 minute 20 seconds. X =-4 -4 times -4 =16. -4 times -4 times -4 = -64. 16 - (-64) =80 (not easy to type out clearly) He was just fitting in numbers to make it work, like @robertloveless4938 said. After all -15 plus -65 also equals -80 but that doesn't work in the equation. You either have to guess -4 or just keep trying numbers until it works.
сразу понятно, что Х должен быт отрицательным чётным числом: минус четыре: 16+64.
I cheated. I immediately knew x had to be negative, then I plugged in numbers, starting with -3 (answer =36), and worked the numbers. . Fortunately, I didn't have to go past 4.
You cheated no more than "Learncommunolizer did ! He had to know that X equaled -4 to plug in his equation at the 1:20 ish point. But YES, it was clear it had to be negative.
sqrt(negative number)... When I was young I could be killed for this.
Too easy. Solve X^3 - X^2 = 79 using REAL algebra.
x^2 - 3^2 = 79; solve for x. No calculators please.
Square root of 70?
@@mohamedzafir8566 Sorry, I mean to write X^3 - X^2 = 79
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I can’t do it
Please I have never done these maths so remove it from me am understanding nothing
X = -4
-4
4+y✓5+y
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