Answer:
The bones were 12,485 years old at the time they were discovered.
Step-by-step explanation:
Amount of the element:
The amount of the element after t years is given by the following equation, considering the decay rate proportional to the amount present:

In which A(0) is the initial amount and k is the decay rate, as a decimal.
The radioactive element carbon-14 has a half-life of 5750 years.
This means that
, and we use this to find k. So







So

A scientist determined that the bones from a mastodon had lost 77.8 % of their carbon-14. How old were the bones at the time they were discovered?
Had 100 - 77.8 = 22.2% remaining, so this is t for which:

Then






The bones were 12,485 years old at the time they were discovered.
2.10 is the answer to the nearest 10th
f(x) = x²<span> - 5x + 1
f(-3) = (-3)</span>² - 5(-3) + 1
<span>
f(-3) = 25
</span>--------------------------------------------------<span>
Answer: f(-3) = 25 (Answer C)
</span>--------------------------------------------------
Answer:
He invested $1200 and had a balance of $1260 after 3 years.
Answer:
The height of rectangle is 5 inches
Step-by-step explanation:
<u><em>The correct question is</em></u>
A rectangle is drawn so the width is 7 inches longer than the height. If the rectangle’s diagonal measurement is 13 inches, Find the height
Let
x -----> the width of the rectangle in inches
y ----> the height of the rectangle in inches
d ---> diagonal measurement of the rectangle in inches
we know that
Applying the Pythagorean Theorem

we have

so

----> equation A
---> equation B
substitute equation B in equation A

solve for y



solve the quadratic equation by graphing
using a graphing tool
The solution is y=5
see the attached figure
therefore
The height of rectangle is 5 inches