Can someone please help me with #7,8, and 10. No links please. Thank you!!

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?

Write the expression in complete factored form. 5n_(c - 3) - n(c - 3) =

How many quarts of a 50% solution of acid must be added to 20 quarts of a 20% solution of acid in order to get a 40% solution of acid?