Respostas

2013-09-16T23:34:18-03:00
(x-3).(x+4)=0
 x^{2} +4x-3x-12=0
 x^{2} +x-12=0

∆ = b²- 4.a.c
∆ = 1²- 4.1.(-12)
∆ = 1 + 48
∆ = 49

x' = (- b + √∆) / 2.a
x' = (- 1 + √49) / 2.1
x' = (- 1 + 7) / 2
x' = 6 / 2
x' = 3

x'' = (- b - √∆) / 2.a
x'' = (- 1 - √49) / 2.1
x'' = (- 1 - 7) / 2
x'' = 8 / 2
x'' = 4

S = { 3 , 4 }