Exercice 2 Développer chacune des expressions littérales suivantes : D= (9x+3)^2 B = (7x + 7) x (7x- 7) E = -(10x - 3)^2 C = (x- 5)^2 F=(7/9x + 1/5)^2

Réponse :

D = (9x+3)^2

D = (9x)^2 + 2*9x*3 + 3^2

D = 81x2 + 54x + 9

B = (7x + 7) * (7x - 7)

B = (7x * 7x) - (7x * 7) + (7*7x) - (7 * 7)

B = 49x2 - 49x + 49x - 49

B = 49x2 - 49

E = (-10x - 3) ^ 2

E = (-10x^2 - 2*10x*-3 - (-3^2))

E = (100x2 - (-60x) -(-9)

E = 100x2 + 60x + 9

C = (x-5)^2

C = x2 + 2*x*5 - (5)^2

C = x2 + 10x + 25

F = (7/9x + 1/5)^2

F = (7/9x)^2 + (2*7 / 9*x*5) + (1/5)^2

F = 49/81x2 + 14/45x + 1/25

Explications étape par étape :