X=5, if that’s what you’re solving for
D, sense there are no repeating numbers in the input (Y)
Since <em>x</em> is the number of 14-year periods, the first thing we do is divide 28 years by 14. 28/14=2. Now we use that in our function,

.

There will be 220 foxes after 28 years.
∛(2x + 5) - 3 = 0
Add 3 to both sides
∛(2x + 5) = 3
Cube both sides
2x + 5 = 27
Subtract 5 from both sides
2x = 22
Divide both sides by 2
x=11
There's your answer. Have an awesome day! :)