Réponses

Meilleure réponse !
2014-04-08T14:32:21+02:00
1)
A = 12a²+20a+9a+15=12a²+29a+15
B=12a²-21a-8a+14
12a²-29a+14

C=20a²+5a+28a+7
20a²+33a+7

D=-2y-14
E=-5x+15

2)
A=5(x+b)
B=3(x-y)
C=2(4a-a)
D=4x(x-4x)

3)
A=2+a-b+3=5+a-b

B=-a-b-a+b-a-b-a+b=-4a

C=5+x+7-b=12+x-b
2014-04-08T14:53:58+02:00
K (a+b) = ka + kb
ka-kb = k (a-b)

A= (4 a+3) (3a+5) = 12 a² + 20a + 9 a + 15 = 12 a² + 29 a +15
B= (3a-2) (4a-7) = 12a² -21 a - 8a -14 = 12 a² - 29 a -14
C= (5a+7) (4a+1) = 20a² + 5a +28 a+7 = 20a² + 33 a 7
D= -2(y+7) = -2 y - 14
E= -5 (x-3) = -5x +15

2) A = 5 x + 5b = 5 (x+b)
   B= 3 x-3 y = 3 (x-y)
c= 8a - 2a = 2 ( 4a-a)
D= 4 x²- 16 x² = 4x ( x -4 x)

3/A =  2 + (a-b+3) = 2 + a-b + 3 = 5 + a - b
 B = - (a+b) - (a+b) + (-a-b) + (-a+b) = -a-b -a -b -a -b -a + b = -4 a - 2 b
 C= 5 - (-x-7+b) = 5 + x +7 -b = 12 +x - b