Question

Resolva essas equações:

a) x + 7 = 3x - 1 b) x - 5x = 6 - 2x c)x + 4 + 3x = 1 - x d) 3 (x - 1)+2x = x + 7

e) 12 - ( 1 + 3x) = 5 ( x - 1 )   f) 7x - 3 (x - 1) + 2 = x - 1   

g) x - 1 sobre 2 - x + 1 sobre 3= x sobre 4   

h) 2 + x sobre 3 - x - 1 sobre 2 = x sobre 3 + 2 

Answer 1

a)
x + 7 = 3x - 1
7 + 1 = 3x - x
8 = 2x
2x = 8
x = 8/2
x = 4

¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨

b)
x - 5x = 6 - 2x
- 4x = 6 - 2x
- 6 = - 2x + 4x
- 6 = 2x
2x = - 6
x = - 6/2
x = - 3

¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨
c)
x + 4 + 3x = 1 - x
4x + 4 = 1 - x
4x + x = 1 - 4
5x = - 3
x = - 3/5
¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨
d)

3.(x - 1) + 2x = x + 7 
3x - 3 + 2x = x + 7
3x + 2x - 3 = x + 7
5x - 3 = x + 7
5x - x = 7 + 3
4x = 10

x = 10  (:2)
      ------
       4   (:2)

x =   5
      ----
        2
¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨

e)
12 - ( 1 + 3x) = 5 ( x - 1 )
12 - 1 - 3x = 5x - 5
11 - 3x = 5x - 5
11 + 5 = 5x + 3x
16 = 8x
8x = 16
x = 16/8
x = 2

¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨
f)
7x - 3 (x - 1) + 2 = x - 1
7x - 3x + 3 + 2 = x - 1
4x + 5 = x - 1
4x - x = - 1 - 5
3x = - 6
x = - 6/3
x = - 2