Réponse :
71) factorisation
a) x³ - 8 x² + 16 x = x(x² - 8 x + 16) = x(x - 4)²
b) (y - 5)² - 4(x - 2)² = (y - 5)² - (2(x - 2))² = ((y - 5 + 2(x - 2)((y - 5 - 2(x-2))
= (y - 5 + 2 x - 4)(y - 5 - 2 x + 4) = (y + 2 x - 9)(y - 2 x - 1)
c) 25 x² + 10 x + 1 + (x + 4)(5 x + 1) = (5 x + 1)² + (x + 4)(5 x + 1)
= (5 x + 1)(5 x + 1 + x + 4) = (5 x + 1)(6 x + 5)
d) (x + 3)² - (2 x + 1)² + (x + 6)(3 x + 4)
= (x + 3 + 2 x + 1)(x + 3 - 2 x - 1) + (x + 6)(3 x + 4)
= (3 x + 4)(2 - x) + (x + 6)(3 x + 4)
= (3 x + 4)(2 - x + x + 6)
= 8(3 x + 4)
Explications étape par étape
