Question

(X+1) . (X-2) = - 4??

Answer 1

Primeiro faz distributiva:
(x+1) . (x-2) =
x^2 - 2x + x - 2
x^2 - x - 2

Delta e Baskhara

1)
∆= 1 - 4 . 1 . -2
∆= 1 - 4 . - 2
∆= 1 + 8 = 9

2)
x= (1 +/- √9) / 2

x1= (1 + 3) / 2
x1= 4/2 = 2

x2= (1 - 3) / 2
x2= -2 / 2 = -1

Resp: X1= 2 e X2= -1