Ill give you 30 points if you answer my physics question​

3(10x-y)-5(x-y^2) need this solved asap

Can someone 50 first drop menu 0.80 or 0.75 or 1.20 or 4.00 second drop menu 4.00 or 0.75 or 0.25 or 3.75 3rd 15,6,10, or 9 4th yes or no

Identify the type of observational study described. a statistical analyst obtains data about ankle injuries by examining a hospital's records from the past 3 years. cross-sectional retrospective prospective