bjr

(x-5) (x+5) = x² - 5² = x² - 25

(6x-7) (6x+7) = (6x)² - 7² = 36x² - 49

(2x+5) (2x-5) = (2x)² - 5² = 4x² - 25

puisque (a-b) (a+b) = a² - b²

Bonjour '

3ème Identité remarquable :

(x-5)(x+5) = (x^2)-5^2= x^2 - 25

(6x-7)(6x+7) =(6x^2)-7^2= 36x^2- 49

Bon courage.