1. **State the problem:** We need to express the total yearly amount paid under Plan A as a function of the dollars of merchandise purchased, $x$. 2. **Identify the components of Plan A:** - Annual membership fee: 125 - Percentage of list price paid: 30% or 0.30 3. **Write the formula:** The total cost $f(x)$ is the sum of the membership fee and 30% of the merchandise cost: $$f(x) = 125 + 0.30x$$ 4. **Explanation:** - The membership fee is a fixed cost, so it is added directly. - The merchandise cost is multiplied by 0.30 because you pay 30% of the list price. 5. **Final answer:** $$f(x) = 125 + 0.30x$$ This function gives the total yearly amount paid under Plan A based on the amount $x$ spent on merchandise.