Réponse :
a)2(x+9)=4x b)5(x-2)=4x+9 <=>
2x +18 = 4x <=> 18 = 4x -2x 5x -10 = 4x + 9 <=>
<=> 18 = 2x 5x - 4x -10 = 9 <=>
x = 9 + 10 <=>
<=> x = 9 x = 19
S= {9} S = {19}
c)3(x-4)=-5x-4 d)x+5=4(x+1)+7
3x - 12 = -5x -4 x +5 = 4x + 4 + 7
3x + 5x = -4 + 12 5 - 4 -7 = 4x - x
8x = 8 -6 = 3x
x = 1 x = -2
S = {1} S= {-2}
e)3x-7=-2(x-4). f)4(x+5) = 10(x-3)
3x - 7 = -2x + 8 4x + 20 = 10x - 30
3x + 2x = 8 +7 20 +30 = 10x - 4x
5x = 15 50 = 6x
x = 3 25 = 3x
S = {3} x = 25/3
S = {25/3}
