Question

Resolva as equações
a)3x+10=100
b) 4x+20=200
c) 7x-20=190
d) 9x+1=81
e) 4x-10=2x-100
f) 9x+30=6x+330
g) 7x-40=5x-300
h) 4x-32=x-158

Answer 1

a)

3x + 10 = 100
3x = 100 - 10
3x = 90 
x = 90/3
x = 30

b)

4x + 20 = 200
4x = 200 - 20
4x = 180
x = 180/4
x = 45

c)

7x - 20 = 190
7x = 190 + 20
7x = 210
x = 210/7
x = 30

d)

9x + 1 = 81
9x = 81 - 1
9x = 80
x = 80/9

e)

4x - 10 = 2x - 100
4x - 2x = -100 + 10
2x = -90
x = -90/2
x = -45

f)

9x + 30 = 6x + 330
9x - 6x = 330 - 30
3x = 300
x = 300/3
x = 100

g)

7x - 40 = 5x - 300
7x - 5x = -300 + 40
2x = -260
x = -260/2
x = -180

h)

4x - 32 = x - 158
4x - x = -158 + 32
3x = -126
x = -126/3
x = -42