#### Answer

a) f(1)=2
b) Limit does not exist .
c)f(4) does not exist.
d)$\lim\limits_{x \to 4}$ f(x) = 2

#### Work Step by Step

a) f(1)=2
b) Limit does not exist because the limit on the left side does not equal limit on the right side.
c)f(4) does not exist because there is a hole at x=4.
d)$\lim\limits_{x \to -4}$ f(x) = 2, and $\lim\limits_{x \to +4}$ f(x) = 2, so the limit at x=4 is 2 even though f(4) doesn't exist.