Bonjour
1) Développer :
(2x-3)(2x-3)-(2x-3)(2x+3)
= 4x² - 6x - 6x + 9 - (4x² + 6x - 6x - 9)
= 4x² - 6x - 6x + 9 - 4x² + 9
= - 12x + 18.
2) Factoriser :
(2x-3)(2x-3)-(2x-3)(2x+3)
= (2x - 3) [(2x - 3) - (2x - 3)]
= (2x - 3) (2x - 3 - 2x - 3)
= - 6 (2x - 3)
