Question 934043
{{{2/x^6-4/x^3=0}}}


Lowest or simplest common denominator is x^6, so .....


....


{{{2/x^6-4x^3/x^6=0}}}


{{{(2-4x^3)/x^6=0}}}


You only want to find x to make numerator zero, and you need not worry about any solution of x=0.


The equation is not quadratic in type.  Any u-substitution neither seems necessary.


{{{2(1-2x^3)=0}}}
{{{1-2x^3=0}}}
{{{2x^3=1}}}


{{{x^3=1/2}}}


{{{highlight(x=root(3,(1/2)))}}} and you could rationalize the denominator if you want.