Answer:
400
Step-by-step explanation:
You want to know the number of foxes predicted after 42 years by y = 50·2^x, where x is measured in 14-year periods.
42 years is 42/14 = 3 14-year periods. Using x=3 in the equation, we predict ...
y = 50·2^3 = 50·8 = 400
foxes.
After 42 years, there will be 400 foxes.
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Additional comment
It is often convenient to use time measured in 1-year periods. In that case, the equation could be written ...
y = 50·2^(t/14)
Then t/14 is the number of 14-year periods when t is in years.
