[(x+2)/(x^2-2x)-(x-1)/(x^2-4x+4)]/[(x-4)/x]=[(x+2)/(x^2-2x)-(x-1)/(x^2-4x+4)]*x/(x-4)={[(x+2)(x+2)-(x-1)x]/x(x-2)^2}*x/(x-4)=(x-4)/x(x-2)^2 * x/(x-4)=1/(x-2)^2