$($Present value of an annuity$)$ What is the present value of the following annuities?

a$.$ $$2,000$ a year for $9$ years discounted back to the present at $10$ percent.

b$.$ $$80$ a year for $5$ years discounted back to the present at $7$ percent.

c$.$ $$280$ a year for $12$ years discounted back to the present at $11$ percent.

d$.$ $$570$ a year for $6$ years discounted back to the present at $6$ percent.

a$.$ What is the present value of $$2,000$ a year for $9$ years discounted back to the present at $10$ percent?

$ $($Round to the nearest cent.$)$

b$.$ What is the present value of $$80$ a year for $5$ years discounted back to the present at $7$ percent?

$($Round to the nearest cent.$)$

c$.$ What is the present value of $$280$ a year for $12$ years discounted back to the present at $11$ percent?

$ $($Round to the nearest cent.$)$

d$.$ What is the present value of $$570$ a year for $6$ years discounted back to the present at $6$ percent?

$ $($Round to the nearest cent.$)$