What are the first three terms of a geometric sequence in which and the common ratio is 5?

A geometric sequence can always be expressed as:

a(n)=ar^(n-1), a=initial value, r=common ratio, n=term number

We are told that a(5)=25 and r=5 so we can say:

25=a5^(5-1)

25=a5^4

25=625a

a=1/25  so now we know our explicit formula for this geometric sequence:

a(n)=(1/25)(5^(n-1))  and the first three terms will be a(1), a(2), and a(3)

1/25, 1/5, 1