Réponse :
on résout les équation suivantes:
9x-7=-8 <=> 9x = -8 +7
<=> 9x = -1
<=> x = -1/9
alors S = {-1/9}
3x-15=-25-2x <=> 3x + 2x = -25 + 15
<=> 5x = - 10
<=> x = -2
alors S = {-2}
7x+6=-3-5x <=> 7x + 5x = - 3 -6
<=> 12x = -9
<=> x = - 9/12
<=> x = - 3/4
alors S = {-3/4}
3(x-1)=7 <=> 3x - 3 = 7
<=> 3x = 7 + 3
<=> x = 10/3
alors S = {-3/4}
-2(5x+2)=2x <=> -(5x +2) = x
<=> -5x -2 = x
<=> -2 = x + 5x
<=> 6x = -2
<=> x = -2/6
<=> x = - 1/3
alors S = {-1/3}
j'espère avoir aidé
