Answer:
![y=220-15x](https://tex.z-dn.net/?f=y%3D220-15x)
Step-by-step explanation:
Let x represent the number of times Giselle uses the athletic club and y represent money left in account.
We have been given that each time she uses the club, $15 is deducted from the account. The amount used after using the club after x times would be
.
We are also told that Giselle pays $220 in advance on her account at the athletic club.
The money left in account after x uses of athletic club would be money in account initially minus amount used for using the club x times.
![y=220-15x](https://tex.z-dn.net/?f=y%3D220-15x)
Therefore, our required equation would be
.