A 20 year loan requires semiannual payments of $1073.33 including interest at 6.8% compounded semiannually.

a) what was the original amount of the loan?

FV = PMT ((( 1 + i)^n - 1)/i)

i = 0.068 / 2

1073.33 (1 + 0.034)^40 - 1 )

_______________

0.034

FV = 85 704.59

85,704.59 = pv ( 1 + 0.034 )^40

Pv = 22,500

B) What is the loan's balance 8.5 years later (just after the scheduled payment)

22 500 ( 1 + 0.034)^17 or 85 704.59/(1+0.034)^40 - 1 )

thats where i'm stuck