Each number is two times three less than the previous number. Starting with the number 3, build a sequence of 5 numbers.

Answer 1

Not clear what you mean by 2 times 3 less than the previous number.

It can be either

Xn = 2 ( Xn-1 - 3)

In which case the sequence is 3,0,-6,-18,-63

Or

Xn = Xn-1 - 2*3=Xn-1-6

In which case the sequence is 3,-3,-9,-15,-21