The given function is
[tex]g(x)=\frac{1}{8}x-3[/tex][tex]\text{Repalce }x=8a-16\text{ to compute }g(8a-16)\text{.}[/tex]
[tex]g(8a-16)=\frac{1}{8}(8a-16)-3[/tex]
[tex]=\frac{1}{8}\times8a-\frac{1}{8}\times16-3[/tex]
[tex]=a-2-3[/tex]
[tex]=a-5[/tex]
Hence the required answer is
[tex]g(8a-16)=a-5[/tex]
