SOLUTION: Please help with the following questions. I am really confused when it comes to rational expressions. Thanks
Find all numbers for which the rational expression is undefined.
n^
Algebra.Com
Question 237901: Please help with the following questions. I am really confused when it comes to rational expressions. Thanks
Find all numbers for which the rational expression is undefined.
n^3-2n
------
n^2-81
rationalize the denominator
- }
--------------------------------
+ }
Found 2 solutions by solver91311, Earlsdon:
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
A rational expression is undefined for any value of the variable that will make any denominator in the expression equal to zero. Set your denominator expression equal to zero and solve. The roots will be the excluded values.
See http://www.algebra.com/algebra/homework/Radicals/rationalizingdenominators1.lesson
for the second part of your question.
John
Answer by Earlsdon(6294) (Show Source): You can put this solution on YOUR website!
1)
For what value of n is undefined?
The expression is undefined when the denominator is zero, so what value of n would make the denominator equal to zero?
Set the denominator equal to zeor and solve for n.
Add 81 to both sides.
Take the square root of both sides.
or
When n=9 or n=-9, the expression is undefined.
2)
Rationalize the denominator:
Multiply the top and bottom of the fraction by the conjugate of the denominator .
Simplify.
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