Hello
This is a geometric progression and we have the first term and we have to find the common ratio.
first term = a
common ratio = r
[tex]\begin{gathered} a=3 \\ r=\frac{12}{3}=4 \end{gathered}[/tex]The 5th term would be
[tex]\begin{gathered} T_5=ar^4 \\ T_5=3\times4^4 \\ T_5=3\times256 \\ T_5=768 \end{gathered}[/tex]The value of the 5th term of the sequence is 768