To determine the correct linear equation that models the total cost of the hedge trimmer rental, we start by identifying the components of the cost structure given in the problem:
- There is a one-time fee of $20.
- There is an additional $30 charge for each day of rental.
The total cost \( y \) can be expressed as a function of the number of rental days \( x \):
- The one-time fee contributes $20 to the total cost.
- The daily rental cost is $30 multiplied by the number of days \( x \).
Thus, the equation for the total cost would be:
\[ y = 30x + 20 \]
This is in the slope-intercept form \( y = mx + b \), where \( m \) is the slope (the cost per day) and \( b \) is the y-intercept (the one-time fee).
Given the provided options, the correct equation that models the total cost over time is:
y = 30x + 20