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Exercice 134 à rendre pour vendredi svp

Exercice 134 À Rendre Pour Vendredi Svp class=

Sagot :

bonsoir

a/
(x+7)(-2x+5) =(x+7)(x-2)
(x+7)(-2x+5) -(x+7)(x-2) =0

b/
(x+7)(-2x+5) -(x+7)(x-2) =0
(x+7)(-2x+5-x+2) =0
(x+7)(-3x+7) =0

x+7 =0                    -3x+7 =0
x = -7                         -3x =-7
                                     x = -7/-3 = 7/3

2/
(-3x-2)(4x+3) =(x-5)(4x+3)
(-3x-2)(4x+3) -(x-5)(4x+3) =0
(4x+3)(-3x-2-x+5) =0
(4x+3)(-4x+3) =0

4x+3 =0                         -4x+3 =0
4x = -3                               -4x =-3
x = -3/4                                 x = -3/-4 =3/4

2x(5x-1) -3x(2x+1) =0
10x²-2x-6x²-3x = 0
4x²-5x =0
x(4x-5) =0

x =0                               4x-5 =0
                                        4x =5
                                          x = 5/4

(5x-1)² -9 =0
(5x-1-3)(5x-1+3) =0
(5x-4)(5x+2) =0

5x-4 =0                        5x+2 =0
5x =4                              5x =-2
x = 4/5                             x = -2/5