bonsoir , besoin d'aide pour mon exo

Ex 1:
1) a. (x-2)² = x²-4x+4

b. (2x-1)(-3x+1) = 2x*(-3x)+2x*1-1*(-3x)-1*1 = -6x²+2x+3x-1 = -6x²+5-1

c. 2(x+3)² = 2(x²+6x+9) = 2x²+12x+18

2)
a. x²-5x = x(x-5)

b. (x-3)(x+1)+2(x+1)
= (x+1)[(x-3)+2]
= (x+1)(x-3+2)
= (x+1)(x-1)

c. x²-6x+9 = (x-3)²