[tex]\bf y=f[\ g(x)\ ]=\cfrac{8}{\sqrt{2x+4}}\\\\
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\begin{cases}
f(x)=\cfrac{8}{\sqrt{x}}\\\\
g(x)=2x+4
\end{cases}\qquad f[\ \underline{g(x)}\ ]=\cfrac{8}{\sqrt{\underline{g(x)}}}\implies f[\ \underline{g(x)}\ ]=\cfrac{8}{\sqrt{\underline{2x+4}}}[/tex]
