Verified answer

Explicação passo-a-passo:

a) 2x - 5x = 90

- 3x = 90

x = 90/-3

x = -30

b) 2/5 x - 10= 20

2/5 x = 20 +10

2/5 x = 30

2x = 30 × 5

2x = 150

x = 150÷2

x = 75

c) 3/10 x - 2/5 x = 5 - 10

3/10 x - 2/5 x = - 5

3 x - 4 x

_______ = -5

10

- 1/10 x = -5

- 1 x = -5 × 10

- x = - 50

x = -50/-1

x = 50

d) 8x - 10x - 5 = 8

- 2x = 8 +5

- 2x = 13

x = 13/-2

x = - 13/2

ou

x = - 6,5

e) 6/2 x - 10/2 x = 0

3x - 5x = 0

- 2x = 0

x = 0/-2

x = 0

f) 3x - 8x +15 = - 20

- 5x +15 = -20

- 5x = -20 - 15

- 5x = - 35

x = -35/-5

x = +7

g) 6x = 12

x = 12/6

x = 2