數學問題二 搵x

x^2(x-2)^2-2x(x-2)-3=0

[x(x-2)]^2-2x(x-2)-3=0

let a=x(x-2), a^2-2a-3=0
(a+1)(a-3)=0
a= -1or 3
a= -1
x(x-2)= -1
x^2-2x+1=0
(x-1)^2=0
x=1

a=3
x(x-2)=3
x^2-2x-3=0
(x+1)(x-3)=0
x= -1or 3