cc
A(x) = (2x+3)² - (2x+3) (1-4x)
1) A(x) = (2x)² + 2*2x*3 + 3² - (2x*1 +2x*(-4x) + 3*1 + 3*(-4x))
A(x) = 4x²+12x+9 - (2x-8x²+3-12x)
A(x) = 12x²+22x+6
2) A(x) = (2x+3)(2x+3) - (2x+3) (1-4x)
A(x) = (2x+3) [(2x+3)-(1-4x)]
A(x) = (2x+3) (6x+2)
si on developpe pour vérif rep q1 = 12x²+4x+18x+6 = 12x²+22x+6 donc q1 ok
3) A(2) = 12*2² + 22*2 + 6 que tu calcules
4) A(0) idem