Question

ATIVIDADE 2 - Resolva as equações abaixo: a) X-3 = 9 c) x + 5 = 20 - 4x b) 4x - 9 = 1 - 2x d) 9x - 4x + 10 = 7x - 30​

Answer 1

Resposta:

x - 3 = 9

x - 3 + 3 = 0

x = 9 + 3

x = 12

x + 5 = 20 - 4x

x + 5 - 5 = 0

x = 20 - 4x - 5

x = - 4x + 15

x + 4x = 15 + 4x

5x = 15

x = 15:5

x = 3

4x - 9 = 1 - 2x

4x - 9 + 9 = 0

4x = 1 - 2x + 9

4x = - 2x + 10

4x + 2x = 10 + 2x

6x = 10

x = 10:6

x = 5/3

9x - 4x + 10 = 7x - 30

5x + 10 = 7x - 30

5x + 10 - 10 = 0

5x = 7x - 30 - 10

5x = 7x - 40

5x - 7x = 40 - 7x

- 2x = - 40

x = - 10 ÷ - 2

x = 20

Answer 2

Resposta:

a) X-3 = 9

x = 9 + 3

x = 12

b) 4x - 9 = 1 - 2x

4x + 2x = 1 + 9

6x = 10

x = 10/6

x = 5/3 ou 1.66666666667

c) x + 5 = 20 - 4x  

x + 4x = 20 - 5

5x = 15

x = 15/5

x = 3

d) 9x - 4x + 10 = 7x - 30​

9x - 4x - 7x = -30 - 10

-2x = -40

x = -40/-2

x = 20