Respostas

2013-12-04T14:57:48-02:00
a)
2x+1 = 4x-9
2x - 4x = -9 - 1
- 2x = - 10                (-1)
2x = 10 
x = 5
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b)
 x + 9 + 3x = 15
x + 3x = 15 - 9
4x = 4
x = 1