(x平方-4)分之(x平方-4x+4) 除以 （x+2）分之（x平方-2x）减去 x分之1 加 1

〔(x^2-4x+4)/(x^2-4)〕/〔(x^2-2x)/(x+2)〕-1/x+1
=〔(x-2)^2/(x+2)(x-2)〕/〔x(x-2)/(x+2)〕-1/x+1
=〔(x-2)/(x+2)〕/〔x(x-2)/(x+2)〕-1/x+1
=1/x-1/x+1
=1