[tex]\bf \begin{cases}
g(x)=x-3\\
h(x)=\sqrt{x}
\end{cases}\qquad
\begin{array}{llll}
(g\circ h)(x)\implies g(~~h(x)~~)\\\\
(g\circ h)(25)\implies g(~~h(25)~~)
\end{array}
\\\\\\
h(25)=\sqrt{25}\implies h(25)=5\qquad thus\implies g(~~h(x)~~)=h(x)-3
\\\\\\
g(~~h(25)~~)=h(25)-3\implies g(~~5~~)=5-3[/tex]
