bonjour,

Factoriser : ( 2 x + 1 )² - ( x - 1 )² = a²-b² qu'on facto (a-b)(a+b)

a² = (2+1)², a = (2x+1)
b² = (x-1)², b = (x-1)


           : 4 x² - ( x + 1 )² = a²-b² qu'on facto (a-b)(a+b)

a² = 4x², a = 2x
b² = (x+1)², b = (x+1)