Bonjour ;
Exercice n° 20 .
A = (x + 4)(x + 3) = x² + 3x + 4x + 12 = x² + 7x + 12 .
B = (y + 3)(2y + 8) = 2y² + 8y + 6y + 24 = 2y² + 14y + 24 .
C = (3z + 4)(5 - 6z) = 15z - 18z² + 20 - 24z = - 18z² - 9z + 20 .
D = (- 7t + 8)(3 - 5t) = - 21t + 35t² + 24 - 40t = 35t² - 61t + 24 .
Exercice n° 13 .
A = 3(x + 6) = 3x + 18 .
B = 5(6 - y) = 30 - 5y .
C = - 7(2z - 3) = - 14z + 21 .
D = - 8(- 5 - 3y) = 40 + 24y .
E = 6(4x - 9) = 24x - 54 .
F = - 12(- 5 + 3z) = 60 - 36z .
