SOLUTION: Please help with this problem. Find all numbers for which the rational expression is undefined. s^3-7s/s^2-64

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Question 442320: Please help with this problem. Find all numbers for which the rational expression is undefined.
s^3-7s/s^2-64
Answer by swincher4391(1107) About Me  (Show Source):
You can put this solution on YOUR website!
A function is only considered undefined if you divide by 0. An exception to this rule would be if the numerator is also 0. Then it is considered in an indeterminate+form.
The best way to approach this would be to factor everything and see if we can simplify.
%28s%5E3-7s%29%2F%28s%5E2-64%29+=+%28s%28s%5E2-7%29%29%2F%28%28s%2B8%29%28s-8%29%29
The numerator is 0 when s =0 or s is %2B-+sqrt%287%29
The denominator is 0 when s = -8 or 8.
All we care about at this point is the denominator since division by 0 gives us an undefined form. It is always good to check that the number doesn't give you a 0%2F0 form... that is why we checked the numerator as well. Good habit.
In this case it doesn't.
So our answers are s+=+-8s+=+8