Question

2) Encontre o valor da incógnita em cada uma das equações:
a) 9x – 2 = 4x + 18
b) 2x – 10 + 7x + 10 = 180
c) 7y – 10 = y + 50
d) 4x – 18 + 3x = 10
e) 2x + 5 + x + 7 = 18
f) 5x – 91 = 4x – 77
g) 7x + 1 = 5x – 7
h) 4x + 5 = x + 20
i) 3(x + 1) + 2(2x – 3) = 5 (x – 1 ) + 8
j) 2(x + 5 ) – 4 = 26
k) 3(x + 3 ) – 5 = 22
l) 2(2x + 7 ) + 3(3x – 5 ) = 3(4x – 5 ) – 1
m) 3( x + 2 ) = 2 ( x – 7)

Answer 1

Resposta:

a) 9x – 2 = 4x + 18

9x - 4x = 18 + 2

5x = 20

x = 20/5 = 4

b) 2x – 10 + 7x + 10 = 180

2x + 7x = 180 + 10 - 10

9x = 180

x = 180/9 = 20

c) 7y – 10 = y + 50

7y - y = 50 + 10

6y = 60

y = 60/6 = 10

d) 4x – 18 + 3x = 10

4x + 3x = 10 + 18

7x = 28

x = 28/7 = 4

e) 2x + 5 + x + 7 = 18

2x + x = 18 - 5 - 7

3x = 6

x = 6/3 = 2

f) 5x – 91 = 4x – 77

5x - 4x = -77 + 91

x = 14

g) 7x + 1 = 5x – 7

7x - 5x = -7 - 1

2x = -8

x = -8 /2 = -4

h) 4x + 5 = x + 20

4x - x = 20 - 5

3x = 15

x = 15/3 = 5

i) 3(x + 1) + 2(2x – 3) = 5 (x – 1 ) + 8

3x + 3 + 4x - 6 = 5x - 5 + 8

3x + 4x - 5x = - 5 + 8 - 3 + 6

2x = 6

x = 6/2 = 3

j) 2(x + 5 ) – 4 = 26

2x + 10 - 4 = 26

2x = 26 - 10 + 4

2x = 20

x = 20/2 = 10

k) 3(x + 3 ) – 5 = 22

3x + 9 - 5 = 22

3x = 22 - 9 + 5

3x = 18

x = 18/3 = 6

l) 2(2x + 7 ) + 3(3x – 5 ) = 3(4x – 5 ) – 1

4x + 14 + 9x - 15 = 12x - 15 - 1

4x + 9x - 12x = - 15 - 1 - 14 + 15

x = - 15

m) 3( x + 2 ) = 2 ( x – 7)

3x + 6 = 2x - 14

3x - 2x = - 14 - 6

x = - 20

Explicação passo a passo: