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) ! ^^
