（x+2/x-2+4/x平方-4x+4）÷x/x-2*x-2/x
=[(x+2)/(x-2)+4/(x-2)²]÷x/(x-2)*(x-2)/x
=(x²-4+4)/(x-2)²*(x-2)/x*(x-2)/x
=x²/(x-2)²*(x-2)²/x²
=1