Just asking, what book is it?
Answer:
and 
Step-by-step explanation:
The equation of the isotope decay is:

14-Carbon has a half-life of 5568 years, the time constant of the isotope is:


The decay time is:
(There is no a year 0 in chronology).

Lastly, the relative amount is estimated by direct substitution:





Answer:
nonagon - 9
Step-by-step explanation:
- pentagon - 5
- nonagon - 9
- hexagon - 6
- octagon - 8
Answer:
It's the second option, a-5