Respostas

2014-08-17T22:23:17-03:00

x²-xy-6=0
x²-x(4-x)-6=0
x²-4x+x²-6=0
2x²-4x-6=0

Δ=b²-4.a.a.c
Δ=4²-4.2.(-6)
Δ=16+48
Δ=64

baskara: x=-b=+- √Δ/2a
x=-(-4)=+-√64/2a
x=4+-8/2
x'=4+8/2 ⇒ x'=12/2 ⇒x'=6
x''=4-8/2 ⇒x''=-4/2 ⇒x''=-2

espero que tenha ajudado