Question

Resolva as equações:
a)5(3-x)-4x=18
b)6(3x+2)-8= -2
c) -3(x-5)-2(2x+1)= -8

Answer 1

a)
5.(3 - x) - 4x = 18
15 - 5x - 4x = 18
15 - 9x = 18
15 - 18 = 9x
- 3 = 9x
9x = - 3
x = - 3  (:3)
      ------
        9  (:3)

x =  - 1
       ------
         3

¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨
b)
6.(3x + 2) - 8 = - 2
18x + 12 - 8 = - 2
18x + 4 = - 2
18x = - 2 - 4
18x = - 6
x = - 6   (:6)       - 1
      -----        =  ------
       18  (:6)         3


c)
 - 3.(x - 5) - 2.(2x + 1) = - 8
- 3x + 15 - 4x - 2 = - 8
- 7x + 13 = - 8
- 7x = - 8 - 13
- 7x = - 21 (-1)
7x = 21
x = 21/7
x = 3