Find the 10th term of the geometric sequence 9,-18,36…

Explanation:

a = 9 = first term

r = -2 = common ratio

We multiply each term by -2 to generate the next term

The nth term for this geometric sequence is a*(r)^(n-1) which becomes 9(-2)^(n-1)

If you tried plugging in say n = 2, you should find that,

9(-2)^(n-1)

9(-2)^(2-1)

9(-2)^1

9(-2)

-18

So that confirms the second term. I'll let you try the other values of n to confirm it further.

From here, you plug in n = 10 to find the tenth term

9(-2)^(n-1)

9(-2)^(10-1)

9(-2)^9

9(-512)

-4608

y = x + 95

y = 42 + 95

y=137 mm hg