Answer
$x=17$
Work Step by Step
Squaring both sides of the given equation, $
\sqrt{5x-4}=9
,$ then the solution/s is/are
\begin{array}{l}\require{cancel}
5x-4=81
\\\\
5x=81+4
\\\\
5x=85
\\\\
x=\dfrac{85}{5}
\\\\
x=17
.\end{array}
Upon checking, $
x=17
$ satisfies the original equation.