Respostas

2014-02-23T12:17:56-03:00
X²-4x-3x-8=0
x²-7x-8=0
Δ= (-7)² -4. 1.(-8)
Δ= 49+32
Δ=81

X= (-(-7)+/-√81)/2
X =( 7 +/- 9)/2
X= 8 e -1