Answer
a) $4.$
b) $16.$
c) $16.$
Work Step by Step
a)By Theorem $1.3: $ $\lim\limits_{x\to c} p(x)=p(c)$
$\lim\limits_{x\to-3}f(x)=-3+7=4.$
b)By Theorem $1.3: $ $\lim\limits_{x\to c} p(x)=p(c)$
$\lim\limits_{x\to4}g(x)=(4)^2=16.$
c)By Theorem $1.5: \lim\limits_{x\to c}(f(g(x)))=f(\lim\limits_{x\to c}g(x)).$
$\lim\limits_{x\to-3}g(f(x))=g(\lim\limits_{x\to-3}f(x))=g(4)=16.$