Respostas

2014-06-10T14:22:25-03:00
A)2x+12=-4x
2x+4x=-12
6x=-12
x=-12/6
x=-2

b)4x+12x=21x-6
4x-21x+12x=-6
-5x=-6
x=-6/-5

c)8x+5=2x-10
8x-2x=-10-5
6x=-15
x=-15/6
x=-5/2