y=5(1.5)^x
I divided 16.875 by 7.5, which is 2.25 Since the multiplier was used twice, I found out the square root of 2.25, which is 1.5. So now we know that the multiplier is 5.
Then I divided 7.5 by 1.5 to get the initial value, since 7.5 is the value in the first spot. 7.5 divided by 1.5 is 5.
Multiplier = 1.5
Initial Value = 5
y=5(1.5)^x