in an exponential sequences the sum of third and fourth term is 3 while the sum of the fifth and six term is 27. find the common ratio
ar^2 + ar^3 = 3 ----> ar^2(1 + r) = 3
ar^4 + ar^5 = 27 ----> ar^4(1+r) = 27
divide the 2nd by the 1st:
ar^4(1+r) / ( ar^2(1 + r) ) = 27/3
r^2 = 9
r = ±3