Respostas

2014-08-07T15:32:36-03:00
15z + 3 - 9z
6z= 3
z= 6/3
z= 2
1 5 1
2014-08-07T15:34:15-03:00
15z+3-9z
15z-9z=3
19z=3
z=3÷19
z=6.3 
1 5 1