Question

Resolva as seguintes equações do primeiro grau com uma incógnita.

a) 4x + 2 = 38

b) 9x = 6x + 12

c) 5x – 1 = 3x + 11

d) 2x + 8 = x + 13

e) 4.(x – 2) – 5.(2 – 3x) = 4.(2x – 6)

f) 23x + 2 = 2 . (3x + 5) - 6

g) 12 – 7 + 4x = 25

h) 5x – 3x = 30 - (-2x + 1)

i) 4x + 10 = 45 – 3x

j) 6x + 15 = 3x - 28

Answer 1

Resposta:

a) 4x + 2 = 38

4x = 38 - 2

4x = 36

x = $\frac{36}{4}$

x = 9  

b) 9x = 6x + 12

9x - 6x = 12

3x = 12

x = 12/3

x = 4

c) 5x – 1 = 3x + 11

5x - 1 - 3x = 11

2x = 11 + 1

2x = 12

x = 12/2

x = 6

d) 2x + 8 = x + 13

2x + 8 - x = 13

x = 13 - 8

x = 5

e) 4.(x – 2) – 5.(2 – 3x) = 4.(2x – 6)

4x - 8 - 10 + 15x = 8x - 24

19x - 18 = 8x - 24

19x - 8x - 18 = - 24

11x = - 24 + 18

11x = - 6

x = -$\frac{6}{11}$

f) 23x + 2 = 2 . (3x + 5) - 6

23x + 2 = 6x + 10 - 6

23x + 2 - 6x = 10 -6

17x +2 = 4

17x = 4 -2

17x = 2

x = $\frac{17}{2}$

g) 12 – 7 + 4x = 25

5 + 4x = 25

4x = 25 - 5

4x = 20

x = 20/4

x = 5

h) 5x – 3x = 30 - (-2x + 1)

2x = 30 + 2x - 1

2x - 2x = 30 - 1

= 29

i) 4x + 10 = 45 – 3x

4x + 10 + 3x = 45

7x = 45 - 10

7x = 35

x = 35/7

x = 5

j) 6x + 15 = 3x - 28

6x + 15 - 3x = - 28

3x = -28 - 15

3x = - 43

x = -$\frac{43}{3}$