Question

Find the 8th term of the geometric sequence 3, -12, 48, ...

Answer 1

a(8) = -49152

Explanation:

Step 1: Find r

-12/3 = 4

Step 2: Write geometric explicit formula

`a_(n) = 3(4)^(n-1)`

Step 3: Plug in 8th term for n

`a_(8) = 3(4)^(7)`

a(8) = -49152

Alternatively you can find r then multiply 3 by -4 8 times.