Given that $\displaystyle \lim_{x \to a} f(x)=3$, $\displaystyle \lim_{x \to a} g(x)=0$, and $\displaystyle \lim_{x \to a} h(x)=7$, find the limits that exist. Enter DNE if the limit doesn't exist.

(a) $\displaystyle \lim_{x \to a} [f(x)+h(x)]=$ help (limits)
(b) $\displaystyle \lim_{x \to a} [f(x)]^2=$ help (limits)
(c) $\displaystyle \lim_{x \to a} \sqrt[3]{h(x)}=$ help (limits)
(d) $\displaystyle \lim_{x \to a} \frac{1}{f(x)}=$ help (limits)
(e) $\displaystyle \lim_{x \to a} \frac{f(x)}{h(x)}=$ help (limits)
(f) $\displaystyle \lim_{x \to a} \frac{g(x)}{f(x)}=$ help (limits)
(g) $\displaystyle \lim_{x \to a} \frac{f(x)}{g(x)}=$ help (limits)
(h) $\displaystyle \lim_{x \to a} \frac{2f(x)}{h(x)-f(x)}=$ help (limits)