Find the three arithmetic means between 7 and 21.

Arithmetic mean of 7 , 21
(7 + 21) /2   = 14

Arithmetic mean of 7 and 14
(7+ 14) /2   = 10.5

Arithmetic mean of 14 and 21
(21 + 14)/2 =17.5

so, the three arithmetic means would be : 10.5 , 14 , and 17.5

hope this helps

Part A: Geometric Sequence

Part B:

Part C: a₈ = 512

Step-by-step explanation:

When we find the common ratio between the y-values (x-values are n inputs), we should see that we get r = 2. That means we have a geometric sequence.

Because we have a geometric sequence, our recursive formula is: . Simply plug in our known variables:

Now we need to find what y is when x = 8, so (I used explicit formula):

a₈ = 512