Réponse:
A=(2x+3)^2 = (2x+3)(2x+3) = 4x^2 + 6x + 6x + 9 = 4x^2+12x+9
B=(3x+1)(3x+1) = 9x^2 + 3x + 3x + 1 = 9x^2+6x+1
C=(4x-2)(4x-2)= 16x^2 - 8x - 8x +4 = 16x^2 - 16x +4
D=(5x-3)(5x-3)= 25x^2 - 15x - 15x + 9= 25x^2 - 30x + 9
E= 36x^2 - 30x + 30x - 25 = 36x^2 - 25
F= 49x^2 + 14x - 14x - 4 = 49x^2 - 4
