Respostas

2014-08-05T19:12:47-03:00
2014-08-05T19:17:05-03:00
10(x-1) -7(x+1)=4
10x-10 -7(x+1)=4
10x-10-7x-7 = 4
10x-7x = +10+7+4

3x = 21 

X= 21/3

x = 7