Answer:
11 music lessons.
Explanation:
We know that membership costs $165 and members pay $25 per music lesson.
So, we can write the following expression:
![165+25m](https://img.qammunity.org/2021/formulas/mathematics/high-school/ytkghxad9oirinvd11t5qi6w4rr8wadoy9.png)
The 165 represents the one-time membership fee and the 25m represents the cost for m music lessons.
We know that non-members pay no membership fee but their cost per lesson is $40. So:
![40m](https://img.qammunity.org/2021/formulas/mathematics/high-school/dyrro25s7bi7qdcrchdvopj81pexf7pwvr.png)
Represents the cost for non-members for m music lessons.
We want to find how many music lessons would have to be taken for the cost to be the same for both members and non-members. So, we can set the expressions equal to each other:
![165+25m=40m](https://img.qammunity.org/2021/formulas/mathematics/high-school/nv8x0ccuughmrtn3zj7cxhoknw6gokp4bc.png)
And solve for m. Let's subtract 25m from both sides:
![165=15m](https://img.qammunity.org/2021/formulas/mathematics/high-school/4j4ppc9mo0221ibivkkuxut4vmbs9dls80.png)
Now, divide both sides by 15:
![m=11](https://img.qammunity.org/2021/formulas/mathematics/college/q7y6bgzellvswad3my4b0wj7ixzn7glp31.png)
So, at the 11th music lesson, members and non-members will pay the same.
Further Notes:
This means that if a person would only like to take 10 or less lessons, the non-membership is best because there is no initial fee.
However, if a person would like to take 12 or more lessons, than the membership is best because the membership has a lower cost per lesson than the non-membership.
And we're done!