Which equivalent of to y = Ax+ By= C

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?

3382-299=3383- ? fill in the blank?

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.