Afossilized leaf contains 15% of its normal amount of carbon 14. how old is the fossil (to the nearest year)? use 5600 years as the half-life of carbon 14.

Elapsed time = half-life * [log(bgng amt / ending amt) / log(2)]
elapsed time = 5,600 * [log(100/15) / log (2)]
elapsed time = 5,600 * [0.82390874094 / 0.30102999566]
elapsed time = 5,600 * 2.73696
elapsed time = 15,326 years
Source:
http://www.1728.org/halflife.htm

point (-8,-4)

Step-by-step explanation:

You can plot that coordinate and rotate the graph to figure out this point.