Step-by-step explanation:
Given
x² = x + 12
x² - x - 12 = 0
x² - ( 4 - 3)x - 12 = 0
x² - 4x + 3x - 12 = 0
x ( x - 4) + 3 ( x - 4) = 0
( x - 4 ) ( x + 3) = 0
Either
x - 4 = 0
X= 4
Or
x + 3 = 0
x = -3
Therefore x = - 3 , 4
