To find the population of foxes after 30 years, we first need to determine how many 15-year periods are in 30 years. Since 30 divided by 15 equals 2, we have \( x = 2 \).
Using the given function:
\[ y = 45 \times 2^x \]
We substitute \( x = 2 \):
\[ y = 45 \times 2^2 \]
Calculating \( 2^2 \):
\[ 2^2 = 4 \]
Now substitute that back into the equation:
\[ y = 45 \times 4 \]
Calculating \( 45 \times 4 \):
\[ y = 180 \]
Thus, after 30 years, there will be 180 foxes.