Respostas

2014-01-23T23:05:55-02:00
4x2+16x+15=0
8+16x+15=0
16x=0+8+15
16x=23
x=23+16
x=39
2014-01-23T23:37:30-02:00

4x2+16x+15=0
Δ=b²-4.4.15 
Δ=156-140 
Δ=16
x1=-b+4/2.4
x1=-12/8=-6
 x2=-24/-6=4