Respostas

2014-08-30T11:43:28-03:00
(x-1)²-(x-1)(x+4)=(x-1).(x+1)
x²-2x+1 -(x²+4x-x-4)=x²+x-x-1
x²-2x+1-x²-3x+4=x²-1
-5x+5=x²-1
-x²-5x+5+1=0
-x²-5x+6=0

Δ = b² - 4.a.c
Δ = -5² - 4 . -1 . 6
Δ = 25 - 4. -1 . 6
Δ = 49

x = (-b +- √Δ)/2a
x' = (--5 + √49)/2.-1        x'' = (--5 - √49)/2.-1
x' = 12 / -2                     x'' = -2 / -2
x' = -6                           x'' = 1

Somando as raizes: -6+1 = -5
1 5 1