Question 339399
You didn't indicate any values but the procedure is simply to substitute the given value for every occurence of x in the equation.
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As an example, {{{x=20}}}
{{{f(x)=sqrt(2x-10)}}}
{{{f(20)=sqrt(2(20)-10)}}}
{{{f(20)=sqrt(40-10)}}}
{{{highlight(f(20)=sqrt(30))}}}