Développer :
A=(x-6)²-(x-6)(5x+2)= x² - 12x + 36 - ( 5x² +2x -30x -12 )
= x² -12x +36 -5x² +28x +12
= -4x² +16x +48
Factoriser
(x-6)²-(x-6)(5x+2)= ( x-6) (x -6 -5x -2)
= (x -6) (-4x - 8)
Résoudre :
(5x-12)(5x+6)=0
5x -12 =0
5x=12
x = 12/5
5x +6=0
5x=-6
x = -6/5
