Answer
$$-\infty$$
Work Step by Step
Given $$\lim _{x \rightarrow \infty}\frac{7-6x^5}{ x+3 }$$
Then
\begin{align*}
\lim _{x \rightarrow \infty}\frac{7-6x^5}{ x+3 }&=\lim _{x \rightarrow \infty}\frac{7/x-6x^5/x}{ x/x+3/x }\\
&=\lim _{x \rightarrow \infty}\frac{7/x-6x^4}{ 1+3/x }\\
&=-\infty
\end{align*}