Given : In 2016, the coin was worth $75
We need to write the equation after 2016
So year starts at 2016. We take year 2016 as t=0
When t=0, the coin worth $75
(0, 75) , given rate is 4% = 0.04
Rate is increasing every year
For exponential growth , we use formula [tex]y= a(1+r)^t[/tex]
where 'a' initial value in 2016 = 75
r is the rate of interest = 0.04
Plug in the values in the formula
[tex]y= a(1+r)^t[/tex]
[tex]y= 75(1+0.04)^t[/tex]
Required equation is [tex]y= 75(1.04)^t[/tex]