Answer:
r = -3
Step-by-step explanation:
to find r divide the 2nd term by the first:
9/ -3 = -3
to check if this is the same ratio for each number divide it by the ratio to get the number before it:
-27/ -3 = 9
81/ -3 = 27
to find the next three terms multiply the last number by the ratio then repeat
(81)(-3) = -243
(-243)(-3) = 729
(729)(-3) = -2187
