Answer
a) $7; 21; 63; 189; 567;$
b) $r=3$
c) See graph
Work Step by Step
We are given the sequence:
$$a_n=7(3)^{n-1}.$$
a) Determine the first $5$ terms:
$$\begin{align*}
a_1&=7(3)^0=7\\
a_2&=7(3)^1=21\\
a_3&=7(3)^2=63\\
a_4&=7(3)^3=189\\
a_5&=7(3)^4=567.
\end{align*}$$
b) The common ratio is the quotient between each number in the series and the number before it:
$$r=\dfrac{a_{n+1}}{a_n}=\dfrac{7(3)^n}{7(3)^{n-1}}=3.$$
c) Graph the terms $a_1,a_2,a_3,a_4,a_5$:
