Exercice 12 : Développer a.2(x-4) b.-3(2x-1) c.4(4-3t) Exercice 13 : Développer et réduire a.(2x+5)(x+1) b.(2y-1)(3y+2) c.(x+7)(3x-1) d.(2t-3)(2t-1) Merci de bi

Bonjour,

12)

a. 2(x-4) = 2x - 2 × 4 = 2x - 8

b. -3(2x-1) = -3 × 2x - (-3) × 1 = -3 × 2x + 3 × 1 = -6x + 3

c. 4(4-3t) = 4 × 4 - 4 × 3t = 16 - 12t

13)

a. (2x+5)(x+1)  = 2x × x + 2x × 1 + 5x + 5 × 1 = 2x² + 2x + 5x + 5 = 2x² + 7x + 5

b. (2y-1)(3y+2)  = 2y × 3y + 2y × 2 - 1 × 3y - 1 × 2 = 6y² + 4y - 3y - 2 = 6y² + y - 2

c. (x+7)(3x-1)  = x × 3x - x + 7 × 3x - 7 = 3x² - x + 21x - 7 = 3x² + 20x - 7

d. (2t-3)(2t-1) = 2t × 2t - 2t - 3 × 2t + 3 = 4t² - 2t - 6t + 3 = 4t² - 8t + 3

En espérant t'avoir aidé(e) ! ^^