Question

X(6X+12)=90

Answer 1

x（6x+12）=90
解: 6x²+12x=90
x²+2x-15=0
（x+5）（x-3）=0
x=-5或x=3

Answer 2

X(6X+12)=90
6X^2 + 12X = 90
6X^2 + 12X - 90 = 0
Dividing by 6, we get:
X^2 + 2X - 15 = 0
Factoring the left side, we get:
(X + 5)(X - 3) = 0
So the solutions are:
X = -5 or X = 3.
However, we should check both solutions to see if they are valid:
If X = -5, then 6X + 12 = -18, and X(6X+12) = (-5) x (-18) = 90, so this is a solution.
If X = 3, then 6X + 12 = 30, and X(6X+12) = 3 x 30 = 90, so this is also a solution.
Therefore, the solutions are X = -5 or X = 3.