To find out how much Manuel received as a hiring bonus, we can analyze the function \( f(x) = 1500x + 300 \).
In this function:
- The term \( 1500x \) represents his monthly salary, where \( 1500 \) is the amount he earns per month.
- The constant term \( 300 \) represents the hiring bonus he received when he started the job.
Thus, the hiring bonus is \( \text{$}300 \).
So, Manuel received $300 as a hiring bonus.