Respostas

2013-08-19T17:45:00-03:00
A) 7×-5×=12+33
2×=45
×=45/2

b) 5×-30+15=20

5×=35
×=7

c) 7×+14=6×-9+15
×=-23+15
×=-8

d) 8×+8=3×+33
5×=41
×=41/5