Respostas

2014-06-29T21:19:21-03:00
1 -  
9x -3(2x +2) = 15
9x -6x -6 = 15
3x = 15 + 6
3x = 21
   x = 7

2-
5(3-x) = 2(x-4) + 15
15 -5x = 2x -8 +15
-5x -2x = -8 +15 -15
-7x = -8
  x = 8/7

3-
3(2x-1) = -2(x+3)
6x - 3 = -2x -6
6x +2x = -6 +3
8x = -3
  x = - 3/8