I'm assuming for g(x) you mean g(x) = x^2+3 for
.
Going with that...
![\begin{aligned}f(g(x)) &= f\left( x^2+3 \right)~~~~~\text{plug $x^2+3$ in for $x$ in $f(x)$}\\[0.5em]&= 2\cdot ( x^2+3 )~~~~~\text{so $2x$ became $2(x^2+3)$}\\[0.5em]&= 2x^2+6\endaligned}](https://tex.z-dn.net/?f=%5Cbegin%7Baligned%7Df%28g%28x%29%29%20%26%3D%20f%5Cleft%28%20x%5E2%2B3%20%5Cright%29~~~~~%5Ctext%7Bplug%20%24x%5E2%2B3%24%20in%20for%20%24x%24%20in%20%24f%28x%29%24%7D%5C%5C%5B0.5em%5D%26%3D%202%5Ccdot%20%28%20x%5E2%2B3%20%29~~~~~%5Ctext%7Bso%20%242x%24%20became%20%242%28x%5E2%2B3%29%24%7D%5C%5C%5B0.5em%5D%26%3D%202x%5E2%2B6%5Cendaligned%7D)
Just treat the enter g(x) function as a single input for f(x).
6- neither of the treatments helped dispel the green lime.
7-control group- water
8-independent variable- coconut juice
9-dependent variable- green slime
10- homers conclusion would be that neither coconut juice nor water would treat the green slime that had been in his shower.