Bonjour,
1)
G = (3x + 2)² - (5 - 2x) (3x + 2)
G = 9x² + 12x + 4 - (15x + 10 - 6x² - 4x)
G = 9x² + 12x + 4 - 15x - 10 + 6x² + 4x
G = 9x² + 6x² + 12x + 4x - 15x + 4 - 10
G = 15x² + x - 6
2)
G = (3x + 2)² - (5 - 2x) (3x + 2)
G = (3x + 2) (5 - 2x - 3x + 2)
G = (3x + 2) (5x - 3)
3)
G = 15x² + x - 6
G = 15 * (- 2)² + (- 2) - 6
G = 15 * 2 - 8
G = 30 - 8
G = 22
4)
(3x + 2) (5x - 3) = 0
3x + 2 = 0 ou 5x - 3 = 0
3x = - 2 ou 5x = 3
x = - 2/3 ou x = 3/5