[tex]\large\boxed{\begin{array}{l}\underline{\sf Estudo\,do\,sinal\,de\,f(x):}\\\rm f(x)>0\iff x<3\,ou\,x>4\\\rm f(x)<0\iff 30\iff x<3\\\rm g(x)<0\iff x>3\end{array}}[/tex]
[tex]\large\boxed{\begin{array}{l}\underline{\sf Observe\,a\,figura\,que\,eu\,anexei.}\\\rm Assinalando\,o\,intervalo\,positivo\,temos\\\rm \dfrac{f(x)}{g(x)}\geqslant0\iff S=\{x\in\mathbb{R}/x\leqslant4\}\end{array}}[/tex]
