Respostas

2014-06-04T10:01:50-03:00
G) -x = -7 (multiplica por -1)
x = 7

H) -8x = 16
x = 16 / -8
x = -2

I) x/2 = 8
x = 8.2
x = 16

J) x/4 = -5
x = -5.4
x = -20

K) 5x-2=18+3x
5x - 3x = 18 + 2
2x = 20
x = 20/2
x = 10

L) 6x-10=2x+24
6x - 2x = 24 + 10
4x = 34
x = 34 / 4
x = 8,5

M) 5x-2=-3x+7+6
5x + 3x = 7 + 6 + 2
8x = 15
x = 15 / 8
x = 1,875

N) 9-x+2=-5x+3+2x
-x + 5x - 2x = 3 - 9 - 2
2x = -8
x = -8/2
x = -4

O) 3 (x+2) =15
3x + 6 = 15
3x = 15 - 6
3x = 9
x = 9/3
x = 3

P) 7 (x-2) =5 (x+3) 
7x - 14 = 5x + 15
7x - 5x = 15 + 14
2x = 29
x = 29 / 2
x = 14,5

Q) 2 (x-6)= -3 (5+x)
2x - 12 = -15 - 3x
2x + 3x = -15 + 12
5x = -3
x = -3 / 5
x = -0,6

R) x/2 - x/4 = 1/2  → mmc = 4
x/4 - x/4 = 1/4
2x - x = 2
x = 2

S) x/5 + 5 = 7x/5  → mmc = 5
x/5 + 5/5 = 7x/5
x + 25 = 7x
x - 7x = -25
-6x = -25
x = -25 / -6
x = 25/6

OBS : as barras (/) significam divisão 
2 5 2