Alguien sabe cómo resolver estos ejercicios?

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 equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Divide. write in simplest form 41/6 divided by 10