Respostas

2014-02-08T15:00:00-02:00
resolver a equaçao
 (x-1).(x+2)
x² +2x -x -2
x² +x -2
2014-02-08T15:01:35-02:00
(x-1)(x+2)

x²+2x-x-2= x²+x-2

equação de segundo grau:
b²-4ac=  1²-4.1.(-2) = 1+8= 9, √9=3

encontrar as raízes:

-b+-√Δ/ 2.a

x`= -1+3/2.1 = x´=1
x``= -1-3/2.1 = x``=-2

As raízes são 1 e -2.