Question 380619
D=5000x/(x^2+36)
Set D to 400 and solve for x:
400=5000x/(x^2+36)
400(x^2+36) = 5000x
400x^2+14400 = 5000x
400x^2-5000x+14400 = 0
4x^2-50x+144 = 0
2x^2-25x+72 = 0
(2x-9)(x-8) = 0
x = {9/2, 8}
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Solution:
At a distance of 4.5 and 8 miles from the center