Sagot :

A) 11x+3=8x+7
11x-8x=7-3
3x=4
x=4/3
B)8x=12x+4
8x-12x=4
-4x=4
x=-1
C)5+6x=-x-9
6x+x=-9-5
7x=-14
x=-2
D)5x=3x+3
5x-3x=3
2x=3
x=3/2