Need with this plz needs to be done early plzz ill give brainliest and 20 points asap

Determine if the equation defines y as a function of x: 2xy = 1. yes o no

If f(x)=3 over x+2 - square root x-3 then f(7)=

Jody bought 20 shares of amazon at the close price of $121.00. she bought 20 more shares a year later at the price of $127.00. two years later, she sold all of her shares at the price of $133.00. her broker charges $50 for each transaction. after all of these transactions, how much money did jody make?