To determine the meaning of the initial amount in the equation \( y = 45x + 75 \), we can analyze the components:
- \( y \) represents the total amount charged in dollars.
- \( x \) represents the number of hours of repair.
- The term \( 45x \) indicates that there is a charge of $45 for each hour of repair.
- The constant term \( 75 \) represents a fixed amount charged before any hourly charges are applied.
Given this breakdown, the initial amount (the constant term) in the equation indicates a fixed charge for the repair.
Thus, the correct answer is:
C. It means the technician charges a fixed amount of $75 for the repair.