bonjour

A = 16x²+48x+36

A = (4x)²+2×4x×6+6² ( identité remarquable )

A = (4x+6)²

B = 64-25x²

B = 8²-(5x)²

B = (8-5x)(8+5x)

C = 49x²-28x+4

C = (7x)²-2×7x×2+2²

C = (7x-2)²

D = 9x²-25+(3x-5)(2x+15)

D = (3x)²-5²+(3x-5)(2x+15)

D = (3x-5)(3x+5)+(3x-5)(2x+15) [facteur commun 3x-5)

D = (3x-5)[(3x+5)+(2x+15)]

D = (3x-5)(3x+2x+5+15)

D = (3x-5)(5x+20)

D = 5(3x-5)(x+4)