1) A = (2x - 3)² + (2x - 3)(-x + 7)
=[4x² - 12x + 9] - 2x² + 14x + 3x - 21
= 4x² -12x + 9 - 2x² + 14x + 3x - 21
= 2x² + 5x - 12
2) A = (2x - 3)[(2x - 3) + (-x + 7)]
= (2x - 3)(2x - 3 - x + 7)
= (2x - 3)(x + 4)
3) (2x - 3)(x + 4) = 0
2x - 3 = 0 ou x + 4 = 0
2x = 3 ou x = -4
x = 3/2
Il y a donc deux solutions 3/2 et -4
