How to simplify this radical equation

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?

You are at a restaurant and owe $38 for your meal. you want to leave a 20% tip. how much will your tip be?

Complete the solution of the equation. find the value of y when x equals to 6 4x+y=20