Question

3, -9, 27, -81,..... common difference/ratiod = 3r = 9r = -3 d = 12

Answer 1

To find the common ratio we divide the terms by the previous one. In this case we have:

$-\frac{9}{3}=-3$$\frac{27}{-9}=-3$$-\frac{81}{27}=-3$

Therefore, the common ratio is r=-3.