Respostas

A melhor resposta!
2014-02-26T12:45:02-03:00
2014-02-26T13:26:41-03:00
A) x+5=18
x=18-5
x=13

b)
2x+x=7-10x
13x+10x=7
23x=7
x=7/23

c)x+12=2x+9
x-2x=9-12
-x=-3  (multiplica os dois lados por -1)
x=3

d)3(x-7)=5x
3x-21=5x
-21=5x-3x
2x=-21
x=-21/2

e) 5.(x+1)=3.(1-x)
5x+5=3-3x
5x+3x=3-5
8x=-2
x=-2/8
x=-1/4

f) 4.(x-6)= -3
4x-24=-3
4x=24-3
4x=21
x=21/4

g) 4y - 10+y=18+7y

4y+y-7y=18+10
-2y=28
y=-14
1 4 1