To model the given scenario using a piecewise function, we define the function \( y \) (total cost) based on the rental time \( x \) (in hours).
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For \( 0 < x \leq 3 \) (i.e., for 3 hours or less):
- The cost is $15 per hour plus a $20 setup fee.
- The total cost function in this case is: \[ y = 15x + 20 \]
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For \( x > 3 \) (i.e., for more than 3 hours):
- The cost is $12 per hour with no setup fee.
- The total cost function in this case is: \[ y = 12x \]
So the complete piecewise function is: \[ y = \begin{cases} 15x + 20 & \text{if } 0 < x \leq 3 \ 12x & \text{if } x > 3 \end{cases} \]
Now, choosing from the options provided, the correct equation for the function is: \[ y = \begin{cases} 15x + 20 & 0 < x \leq 3 \ 12x & x > 3 \end{cases} \]
This matches with: y={15x+20, 0<x≤3; 12x, x>3}.
Note: The option you might see as "y equals left brace line 1 15 plus 20 comma 0 less than x less than or equal to three line 2 12 comma x greater than 3" has the right structure but might be expressed unclearly, so ensure that you recognize the correct configuration.