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Using an exponential function, it is found that it takes 18.6 days for 80% of the material to decay.
The amount of a substance after t days is modeled by:

In which:
- k is the decay rate, as a decimal.
- A(0) is the initial amount.
The half-life is of 8 days, hence
, and this is used to find k.







Hence:

The time it takes for 80% of the material to decay it t for which
, hence:






It takes 18.6 days for 80% of the material to decay.
To learn more about exponential functions, you can take a look at brainly.com/question/24906920
Answer:
M = 2x² - (ax/3) + by
B = - 3x²y + (xy³/3) - cy
Step-by-step explanation:
Equation 1 is
2x² - (1/3)ax + by - M = 0
M = 2x² - (ax/3) + by
Equation 2
3x²y - (1/3)xy³ + cy + B = 0
B = - 3x²y + (xy³/3) - cy
Hope this Helps!!!
Answer:663
Step-by-step explanation:
The first row is 15,so you have to add three from the first row you and you get 18 and then you keep going and going till you get to the 17th row then you add the numbers together.