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aidez moi svp:
voici la consigne : Factoriser le premier membre de chaque equation puis la résoudre.

a) 3x3 ( c'est 3xau cube ) +2x=0
b)(x+2)(-x+1)+(x-3)(x+2)=0
c)(2x-6)(-x+5)-2(-x+5)=0
d)(5x-8)(x-3)-(x-1)(x-3)=0


Répondre :

bonsoir

a) 3x3 ( c'est 3xau cube ) +2x=0
x(3x²+2) =0

x =0               3x²+2 =0
                      3x² = -2
                        x² = -2/3
                         x = V-2/3 (impossible)

 b)(x+2)(-x+1)+(x-3)(x+2)=0
(x+2)(-x+1+x-3) =0
(x+2)(-2) =0
-2(x+2) =0

x+2 =0
x = -2

c)(2x-6)(-x+5)-2(-x+5)=0
(-x+5)(2x-6-2) =0
(-x+5)(2x-8) =0
2(-x+5)(x-4) =0

-x+5 =0                   x-4 =0
-x = -5                      x = 4
x = 5

d)(5x-8)(x-3)-(x-1)(x-3)=0
(x-3)(5x-8-x+1) =0
(x-3)(4x-7)=0

x-3 = 0                   4x-7 =0
x = 3                          4x =7
                                   x = 7/4