Respostas

2013-11-05T15:32:00-02:00
2x + 1 = x + 11
2x - x = 11 - 1
x = 10
Confirmando:
2 * 10 + 1 = 21
10 + 11 = 21

5x + 2 = 2x - 4
5x - 2x = - 4 - 2
3x = - 6
x = - 6 : 3
x = - 2
Confirmando:
5 * (- 2) + 2 =
- 10 + 2 = - 8

2 * (- 2) - 4 =
- 4 - 4 =
- 8