Help find equation and missing angle

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?

Find the value of x that will make l ll m

0if x and y vary inversely and y=6 as x=7, what is the constant of variation?