[tex]12,36,108,324[/tex]
1) Since we've been told the Explicit Formula for this Geometric Sequence, then we can find the first four terms, namely:
[tex]a_1,a_2,a_3,a_4[/tex]
2) Thus, plugging into each term n=1, n=2,n=3,n=4 we've got the following below:
[tex]\begin{gathered} a_1=4(3)^1=12 \\ a_2=4(3)^2=36 \\ a_3=4(3)^3=108 \\ a_4=4(3)^4=324 \end{gathered}[/tex]
Note that each term is thrice the previous one. And that is the answer.
