bonjour,

pour x = 12

4 + 3x = 4 + 3*12 = 40

7x = 7*12 = 84

(2x+3) (5-x) + 10

= 10x - 2x² + 15 - 3x + 10

= -2x + 7x + 25

et 47 + x (7-2x) - 22

= 47 + 7x - 2x² - 22

= -2x² + 7x + 25

ok

factoriser G

G = (x+5) (7x-3) + (x+5) (2x-4)

G = (x+5) (7x-3 + 2x-4)

il faut finir le calcul :

G = (x+5) (9x - 7)

K = (3x+2)² - (3x+2) (x+7)

K = (3x+2) (3x+2 - (x+7))

= (3x+2) (3x+2-x-7)

= (3x+2) (2x-5)    ok

Réponse :

bonjour,

1)Juste

2)Juste

3)(x+5) (7x-3) + (x+5) (2x-4)

(x+5) [(7x-3)+(2x-4)]

(x+5) [7x-3+2x-4]

(x+5) (9x-7)

4)(3x+2)²-(3x+2) (x+7)

(3x+2)[(3x+2)-(x+7)]

(3x+2)[3x+2-x-7]

(3x+2)(2x+5)