Answer
(a) $0$
(b) factor
(c) $x$
Work Step by Step
Recall:
If $c$ is a zero a polynomial $P$, then:
(i) $x-c$ is a factor of $P(x)$;
(ii) $P(c)=0$; and
(iii) $P$ has $c$ as its $x$-intercept.
Thus, the missing expressions in the given statements are:
(a) $0$
(b) factor
(c) $x$
