Question 984374
I will assume (x-2)/x^2

denominator is x^4

numerator is vdu-udv=x^2(x)-(x-2)(2x)
=(x^3-2x^2+4x)/x^4= (x^2-2x+4)/x^3.  If this is set =0, complex roots, so no max or min.

{{{graph(300,200,-10,10,-10,10,(x-2)/x^2)}}}

If I assume x-(2/x^2)
dy/dx= 1+4x^(-3)

If this is set equal to zero, 
4x^(-3)=-1; x^(-3)=(-1/4), x=-1/4^(1/3), or about -0.63=x

{{{graph(300,200,-10,10,-10,10,x-(2/x^2))}}}