SOLUTION: I am having some difficulty in solving rational expressions. If someone could please explain to me on how to solve when in a word problem.. any help would be greatly appreciated..

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Question 123004: I am having some difficulty in solving rational expressions. If someone could please explain to me on how to solve when in a word problem.. any help would be greatly appreciated....
1. The cost, in millions of dollars, to remove x % of pollution in a lake modeled by C=6000/200-2x
a. What is the cost to remove 75% of the pollutant?
b. What is the cost to remove 90 % of the pollutant?
c. What is the cost to remove 99% of the pollutant?
d. For what value is this equation undefined?
This is not from a textbook...

Answer by checkley71(8403) (Show Source):
You can put this solution on YOUR website!
C=6000/(200-2X) I'LL ASSUME THIS IS THE EQUATION.
C=6000/(200-2*75)
C=6000/(200-150)
C=6000/50
C=120 COST TO REMOVE 75%.
C=6000/(200-2*90)
C=6000/(200-180)
C=6000/20
C=300 COST TO REMOVE 90%.
C=6000/(200-2*99)
C=6000/(200-198)
C=6000/2
C=3000 COST TO REMOVE 99%.
THE EQUATION IS UNDEFINED WHEN YOU USE 100%.
C=6000/(200-200)
C=6000/0 C BECOMES UNDEFINED WHEN YOU IVIDE BY 0.