Question

true or false The following is a geometric sequence.
-2, -6, -18, -54,…

Answer 1

First find the differences between all the numbers.

-2 , -6 , -18, - 54
4 12 36

Note that the difference is not the same throughout the 4 terms. This it is not an arithmetic progression and definitely a geometric sequence. Why? because the difference grows by a multiple of 3.
4*3 = 12
12*3 = 36

Answer 2

ok thanks! what about this one? -5, 25, -125, 625,…

Answer 3

Find the difference first, Note that the difference is not the same.

Answer 4

that makes it false. because theres a difference. right?

Answer 5

Yep.