#### Answer

a) $-5$ and $5$
b) $a_{n+1} = -a_n$, $a_1 = -5$
c) $a_n = 5(-1)^{n}$

#### Work Step by Step

a) The absolute value remains the same while only the signs change. Thus, the next two values are $-5$ and $5$
b) Since the first term is $-5$, $a_1 = -5$
The recursion should only affect the sign of the term.
$a_{n+1} = -a_n$
c) The only thing that changes as the sequence continues is the sign of the number $5$. Every time $n$ is an odd number, the term is $-5$.
$a_n = 5(-1)^{n}$