Respostas

2014-05-27T15:55:15-03:00
3x-3-7=15
3x=15+3+7  
3x= 
x= 25/3
x=8,333
7 2 7
2014-05-27T16:09:28-03:00
3(x-1)-7=15 
3x -3 -7 =15 
3x = 15 +3 +7 
3x= 25 
x= 25/3 
x= 8,333
4 5 4