Assignment: 
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Answer: 
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Explanation: 
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[ Step One ] Follow PEMDAS Order Of Operations; Calculate Within Parenthesis
Note: 

[ Step Two ] Rewrite Equation

[ Step Three ] Calculate Within Parenthesis

[ Step Four ] Rewrite Equation

[ Step Five ] Calculate Exponents

[ Step Six ] Rewrite Equation

[ Step Seven ] Multiply

[ Step Eight ] Rewrite Equation

[ Step Nine ] Subtract

[ Step Ten ] Rewrite Equation

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The equation of the circle:

(h, k) - center
r - radius
We have:

Substitute:

Answer:
56.42 minutes
Step-by-step explanation:
The initial sample= y0 = 800
After 13 minutes , amount = 320
Y= y0e-kt
320 = 800e-k(13)
320/800 = e-k13
0.4 = e-k13
In0.4 = -k13
-0.91629= -k13
0.07048= k
Y = 800e-0.07048t
Minutes when the bacterial present will be 15
15 = 800e-0.07048t
15/800= e-0.07048t
0.01875 = e-0.07048t
In 0.01875 = -0.07048t
-3.97656 = -0.07048t
-3.97656/-0.07048= t
56.42 = t
56.42 minutes
Answer:
15.25 or 15 if you need it to be rounded.
Step-by-step explanation:
-11 on both sides to get 5x=1x+61. Then, -1x on both sides to get 4x=61. Then to find x you do 61 divided by 4 which is 15.25.