Answer:
27 times 9 ^n-3
Step-by-step explanation:
Replace n with 3:
[tex]a_{n} = 3 * 2^{n-1} \\a_{3} = 3 * 2^{3-1} \\a_{3} = 3 * 2^{2} \\a_{3} = 3 * 4\\a_{3} = 12[/tex]
