72. recall the present value of an annuity formula, where ap is the present value, r is the monthly payment, i is the
monthly interest rate, and n is the number of monthly payments: ap=r(1-(1+i)-n/i)
rewrite this formula to isolate

step-by-step explanation:

c.

step-by-step explanation:

because first you have to add the 4x, 9x, and the 7x together and you get 20x and then you add the last numbers up and you get 5and then you put the subtraction sign in there and that's how you get the answer.