Consider the given function,
[tex]g(x)=\frac{3+2x}{-5+x}[/tex]Replace 'x' by '2a' in the given expression,
[tex]\begin{gathered} g(2a)=\frac{3+2(2a)}{-5+2a} \\ g(2a)=\frac{3+4a}{-5+2a} \end{gathered}[/tex]Thus, the required function is,
[tex]g(2a)=\frac{3+4a}{-5+2a}[/tex]