Answer:
1.97 ounces
Step-by-step explanation:
-The exponential decay function is given by the formula:

Given that the half-life is 4 days, we can substitute in the formula to solve the rate of decay for a single half-life:

#Since, 1 week has 7 days, 3 weeks is a 21-day period, thus, t=21.
#We substitute and solve for the amount remaining after 21days of decay:

Hence, the amount remaining after 3 weeks of decays is approximately 1.97 ounces
For example, think about 8.4 - 2.9.
You have to regroup because you can't subract 4 - 9.
4 turns into a 14 since you borrow from the left number, 8.
8 turns into a 7 after that.
Now, you have to subtract 14 - 9 and 7 - 2. You're answer is 5.5.
You can check your work by doing inverse opperations:
By adding:
5.5 + 2.9 = 8.4
Or by subracting 8.4 - 5.5 = 2.9
Hope this helped you! If you need a better explaination or another example, I will be happy to help you! :)
Two circles<span> of </span>radius<span> 4 are </span>tangent<span> to the </span>graph<span> of y^</span>2<span> = </span>4x<span> at the </span>point<span> (</span>1<span>, </span>2<span>). ... I know how to </span>find<span> the </span>tangent<span> line from a circle and a given </span>point<span>, but ... </span>2a2=42. a2=8. a=±2√2. Then1−xc=±2√2<span> and </span>2−yc=±2√2. ... 4 from (1,2<span>), so you could </span>find these<span> centers, and from there the</span>equations<span> of the circle
</span>
Since he’s already at -15, if he writes a check for 7 then he’s subtracting more from his account.
So, -15-7=-22