math
posted by deborah on .
in a certain geometric sequence, the third term is 8 and the sixth term is 125. what is the first term?

ar^2 = 8
ar^5 = 125
divide the 2nd by the 1st ....
r^3 = 128/8
r = 5/2
back into the first
a(25/4) = 8
etc.