Please help asap pretty easy question just stuck

Trish receives $450 on the first of each month. josh receives $450 on the last day of each month. both trish and josh will receive payments for next four years. at a discount rate of 9.5 percent, what is the difference in the present value of these two sets of payments?

The table shows the balance of a money market account over time. write a function that represents the balance y(in dollars) after t years.

Which is the focus of a parabola with equation y2=4x