Step 1 Just observe that this sequence consists multiples of 3.

Step 2

a)

\(\begin{array}{|c|c|}\hline x & 1 & 2 & 3 & 4 & 5 & 6 \\ \hline y & 3 & 6 & 9 & 12 & 15 & 18 \\ \hline \end{array}\)

b) common difference \(\displaystyle={3}\)

zero term \(\displaystyle={0}\)

c) \(\displaystyle{y}={3}{x}\)