Respostas

A melhor resposta!
2014-07-18T16:10:57-03:00
A) 3/7x 2/7 + 4/7+3/7==>

6/49+12/49 = 18/49
1 5 1
perdao.. errei...
3/7.2/6 = 6/42 +. 4/7.3/6= 12/42= 18/42. = 3/7
e a b 12/21
Opa, obrigado.