A sequence can be generated by using "an-3a(n-1)" where a1-6 and n is a whole number greater than 1. What are the first four terms of the sequence?

a. 6,9,12,15
b. 6,18,54,162
c. 6,12,18,24
d. 6,36,216,1296

The correct sequence is:

a. 6, 9, 12, 15

To generate the sequence, we use the formula an = 3a(n-1). Starting with a1 = 3(6) = 18, we get the sequence 6, 9, 12, 15.