845,245,002 is your answer.
21/22
use y2-y1 / x2-x1
(9-(-12)) / (3-(-19))
21/22
First thing to do is to move the constant over to the other side of the equals sign. Then we will complete the square on the x terms. We will take half the linear term, square it, then add it to both sides. Our linear term is 4. Half of 4 is 2, and 2 squared is 4.

. In the process of completing the square we have created a perfect square binomial on the left which is

. A is our answer.
The general expression would be:

In an organism that is 20,000 years old (t = 20000), we would expect:

This menas there would be around 8.898% of carbon-14 remaining in the organism.