Sagot :
Bonjour
4)
4x (x - 2) - (2x - 2)²
= 4x² - 8x - (4x² - 8x + 4)
= 4x² - 8x - 4x² + 8x - 4
= 4x² - 4x² - 8x + 8x - 4
= - 4
5)
5x - 25 = 5 (x - 5)
6)
15x - 15 = 15 (x - 1)
7)
(x - 1) (x + 2) + (x - 1) (2x + 3)
= (x - 1) (x + 2 + 2x +3)
= (x - 1) (3x + 5)