Respostas

2013-09-22T17:29:27-03:00
-3x= -21 .(-1)
3x=21
x=21/3
x=7
2 5 2
2013-09-22T17:31:09-03:00
Se 21=3x entao 3x=21
3x=21
x= \frac{21}{3}
x=7
3 5 3