Question 887856
{{{x-5sqrt(x)-24=0}}}
Substitute from assigning {{{u=sqrt(x)}}}.
{{{u^2-5u-24=0}}}
{{{(u+3)(u-8)=0}}}


{{{u=-3}}}
{{{sqrt(x)=-3=i^2*3}}}
{{{highlight(x=9)}}}


{{{u=8}}}
{{{sqrt(x)=8}}}
{{{highlight(x=64)}}}


You should check each of these solutions of x to be sure each does or does not really satisfy the equation.