To model the car rental cost as a linear function, we need to consider both the fixed charge for renting the car and the variable cost based on the miles driven.
The fixed charge for renting the car is $50, and the variable cost is $0.50 for each mile driven, which can be represented by the variable \( x \).
The total cost function \( f(x) \) can be expressed as:
\[ f(x) = 0.50x + 50 \]
Here, \( 0.50x \) represents the cost based on the miles driven, and \( 50 \) represents the base rental fee.
Thus, the correct function that models the situation is:
f(x) = 0.50x + 50