Respostas

2013-08-08T11:56:58-03:00
1º) - 1/4 + 2/3= (-1/4)/ 3+ (2/3)/4= -3+8/12= 5/12

2º) x + 5/6= 5/12
x= 5/12- 5/6
x= - 5/12