In the problem with the white circle, x=100, in the problem with the blue circle, x might equal 165, but I'm not entirely certain. But I am certain about the first one.
Answer:
A = 20,000
Step-by-step explanation:
200,000 ÷ 10 = 20,000
We need the half-life of C-14 which is 5,730 years.
Now, we will need a half-life equation:
elapsed time = half-life * log (bgng amt / ending amt) / log 2
We'll say beginning amount = 100 and ending amount = 41
elapsed time = 5,730 * log (100/41) / log 2
elapsed time = 5,730 * log (
<span>
<span>
<span>
2.4390243902
</span>
</span>
</span>
) / 0.30102999566
elapsed time = 5,730 * 0.38721614327 / 0.30102999566
elapsed time =
<span>
<span>
</span></span><span><span><span>5,730 * 1.2863041851
</span>
</span>
</span>
<span>elapsed time = 7,370.523 years
Source:
http://www.1728.org/halflife.htm </span>
If an expression is the difference of two squares, it will follow this format:

where a and b are integers or variables.
1)

Since the expression follows the format, it's a DoTS.
2) Since the binomial has an addition sign, it isn't a DoTS.
3)

The second term isn't an integer, so the expression isn't a DoTS.
4)

Since the expression follows the format, it's a DoTS.
Therefore, the first and fourth expressions are differences of two squares.
Answer:
Junk gets 72
Step-by-step explanation:
Leah: Junko: total
1 8 1+8 = 9
The total is 81
81/9 = 9
Multiply each part by 9
Leah: Junko: total
1*9 8*9 9*9
9 72 81