Réponse :
A = (6x-5)² =a²-2ab+b²=
(6x)²-2(6x*5)+5²=
36x²-60x+25
B = -8(-2x-1)(5x-2)=
(16x+8)(5x-2)=
16x*5x + 16x*-2 + 8*5x + 8*-2=
80x²-32x+40x+16 =
80x²+8x+16
C -2x(3-x)-(2-5x)(3x-6)=
(-6x+2x²)-(6x-12-15x²+30x)=
-6x+2x²-6x+12+15x²-30x=
13x²-42x+12
Explications étape par étape
