Given that $\> \displaystyle \lim_{x \rightarrow +\infty} f(x) = -6$, $\> \displaystyle \lim_{x \rightarrow +\infty} g(x) = 2$, $\> \displaystyle \lim_{x \rightarrow +\infty} h(x) = -7$, find the following limits

Enter inf for $\infty$, -inf for $-\infty$, and DNE if the limit does not exist.

(a) $\> \displaystyle \lim_{x \rightarrow +\infty} [f(x) +9 g(x)]\>$

(b) $\> \displaystyle \lim_{x \rightarrow +\infty} [f(x) g(x)]\>$

(c) $\> \displaystyle \lim_{x \rightarrow +\infty} \frac {10} {g(x)}\>$

(d) $\> \displaystyle \lim_{x \rightarrow +\infty} \frac {6 h(x) + 3} {x^2}\>$