The exponential growth of the insect population can be modeled by the equation:
\[ y = y_0 \cdot (1 + r)^x \]
where:
- \(y\) is the population after \(x\) weeks,
- \(y_0\) is the initial population,
- \(r\) is the growth rate (as a decimal),
- \(x\) is the number of weeks.
In this case:
- The initial population \(y_0 = 312\),
- The growth rate \(r = 0.05\) (which is 5% expressed as a decimal).
Substituting these values into the equation gives:
\[ y = 312 \cdot (1 + 0.05)^x \]
So, the exponential equation to model the insect population after \(x\) weeks is:
\[ y = 312 \cdot (1.05)^x \]