Bonjour,
Ex. 3 : distributivité, double distributivité et identités remarquables
A = (x+5)(x-2) = x²-2x+5x-10 = x²+3x-10
B = 3x(7x-3)+(2x+5)(2x-5) = 21x²-9x+(2x)²-5² = 25x²-9x-25
C = (4x+7)(2x-3) = 8x²-12x+14x-21 = 8x²+2x-21
Ex. 4 : identité remarquable (a+b)(a-b) = a²-b²
E = 36x²-25 = (6x)²-5² = (6x+5)(6x-5)
F = 100x²-1 = (10x)²-1² = (10x+1)(10x-1)
G = 49x²-64 = (7x)²-8² = (7x+8)(7x-8)
