Réponse :

A) -3x + 2(4x + 7)

= -3x + 2 x 4  2 x 7

= -3x + 8  + 14

= -3x + 22

B) 3(4x + 8) - 5(3x + 1)

= (3 x 4x + 3 x 8) - (5 x 3x + 5 x 1)

= ( 12x + 24 ) - ( 15x + 5)

= 12x + 24 + 15x - 5

= 27x - 29

C) (5x + 2) (6x + 4)

= 5x x 6x + 5x x 4 + 2 x 6x + 2 x 4

= 30x + 20x + 12x + 8

= 62x + 8

D) (5x - 3) (-4x + 2)

= 5x x (-4x) - 5x x 2 - 3 x (-4x) + 3 x 2

= -20x - 10x + 12 + 6

= -30x + 18

E) (-4 + 3x) (3 + 2x)

= (-4) x 3 + (-4) x 2x + 3x x 3 + 3x x 2x

= -12 + -8 + 9x + 6x

= 9x + 6x - 12 - 8

= 15x - 4

Explications étape par étape