Question

(x+1).(x-2)=0
ajuda a entender o valor de x pf.obg

Answer 1

(x + 1). (x - 2) = 0
x² - 2x + x - 2 = 0
x² - x - 2 = 0

a = 1; b = - 1; c = - 2

Δ = b² - 4ac
Δ = (-1)² - 4.1.(-2)
Δ = 1 + 8
Δ = 9

x = - b + / - √Δ = - ( - 1) + / - √9  
           2a                  2.1

'x = 1 + 3 = 4/2 = 2
       2

x" = 1 - 3 = - 2/2 = - 1
        2

Resp.: x = 2 e x = - 1