In order for the table below to show exponential decay, what must the value of d be in the table below?

d = 18

Let x represent the domain
Let y represent the range.

Assume that y =a*b⁻ˣ

Set x=0:
a*b⁰ = 32
a = 32

Set x=1:
32*b⁻¹ = 24
32 = 24b
b = 32/24

Set x=2:
d = 32*(32/24)⁻²
   = 32*(24/32)²
   = (32*24*24)/(32*32) = 24²/32 = 576/32
   = 18

18