Respuesta :

[tex]\bf \begin{cases} f(x)=x^2-3\\ g(x)=\sqrt{3+x} \end{cases}\\\\ -------------------------------\\\\ f(~~g(x)~~)=[g(x)]^2-3\implies f(~~g(x)~~)=[\sqrt{3+x}]^2-3 \\\\\\ f(~~g(x)~~)=3+x-3\implies \boxed{f(~~g(x)~~)=x}\\\\ -------------------------------\\\\ g(~~f(x)~~)=\sqrt{3+[f(x)]}\implies g(~~f(x)~~)=\sqrt{3+[x^2-3]} \\\\\\ g(~~f(x)~~)=\sqrt{3+x^2-3}\implies g(~~f(x)~~)=\sqrt{x^2} \\\\\\ \boxed{g(~~f(x)~~)=x}[/tex]