The starting weight of the radioactive isotope = 96 grams
Weight after one hour is half of the starting weight. So the weight of the radioactive isotope after 1 hour = 48 grams
After 2 hours the weight is half as compared to the weight after previous hour. So weight after 2 hours = 24 grams.
This means, after every hour the weight is being halved. The half life of radioactive isotope is one hour.
Since after every hour, the weight is being halved, the weight of the isotope can be modeled by an exponential equation.
So,
Initial Weight = W₁ = 96
Change factor = 1/2 = 0.5
The general equation of the sequence will be:

Here t represents the number of hours. Using various values of t we can find the weight of the radioactive isotope at that time.
We can plot the sequence using the above equation. The graph is attached below.
He's correct
there is exactly 1760 yards in a mile
Answer:
C) 21
Step-by-step explanation:
a² + 20² = 29² Use Pythagorean Theorem to solve for a
a² + 400 = 841 Solve for the exponents
- 400 - 400 Subtract 400 from both sides
a² = 441 Take the square root of both sides
a = 21
0.2 = 2/10 = 1/5 but 0.02 = 2/100 = 1/50 so 1/5 > 1/50 :D
The general form of a parabola when using the focus and directrix is:
(x - h)² = 4p(y - k) where (h, k) is the vertex of the parabola and 'p' is distance between vertex and the focus. We use this form due to the fact we can see the parabola will open up based on the directrix being below the focus. Remember that the parabola will hug the focus and run away from the directrix. The formula would be slightly different if the parabola was opening either left or right.
Given a focus of (-2,4) and a directrix of y = 0, we can assume the vertex of the parabola is exactly half way in between the focus and the directrix. The focus and vertex with be stacked one above the other, therefore the vertex will be (-2, 2) and the value of 'p' will be 2. We can now write the equation of the parabola:
(x + 2)² = 4(2)(y - 2)
(x + 2)² = 8(y - 2) Now you can solve this equation for y if you prefer solving for 'y' in terms of 'x'