Respostas

2013-12-09T16:47:42-02:00
(x+8)^2=x^2+12^2
x^2+2.x.8+8^2=x^2+144
x^2+16x+64=x^2+144
x^2-x^2+16x=144-64
0+16x=80
x=80/16
x=5