[tex]\begin{cases} f(x)=x^2\\ g(x)=x-3 \end{cases}\qquad \qquad (g\circ f)(x)\implies g(~~ f(x)~~) \\\\[-0.35em] ~\dotfill\\\\ f(3.5)=(3.5)^2\implies f(3.5)=12.25 \\\\\\ g(~~ f(3.5)~~)\implies g(~~ 12.25~~)=(12.25)-3\implies \stackrel{(g\circ f)(3.5)}{g(~~ 12.25~~)}=9.25[/tex]
