There are many ways to do this.
One such way is
[tex]f(x) = \frac{8}{x}+2[/tex]
[tex]g(x) = x^2[/tex]
So therefore,
[tex]f(x) = \frac{8}{x}+2[/tex]
[tex]f(g(x)) = \frac{8}{g(x)}+2[/tex]
[tex]f(g(x)) = \frac{8}{x^2}+2[/tex]
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Another way to do it is this
[tex]f(x) = \frac{1}{x}+2[/tex]
[tex]g(x) = \frac{1}{8}x^2[/tex]
So,
[tex]f(x) = \frac{1}{x}+2[/tex]
[tex]f(g(x)) = \frac{1}{g(x)}+2[/tex]
[tex]f(g(x)) = \frac{1}{1/8x^2}+2[/tex]
[tex]f(g(x)) = \frac{8}{x^2}+2[/tex]
getting the same result