SOLUTION: Find all numbers for which rational expression is undefined. p^3-8p/p^2-49

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Question 419734: Find all numbers for which rational expression is undefined.
p^3-8p/p^2-49
Found 2 solutions by stanbon, Theo:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Find all numbers for wwhich rational expression is undefined.
p^3-8p/p^2-49
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Factor where you can to get:
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[p(p^2-8))]/[(p-7)(p+7)]
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Undefined when the denominator is zero.
Undefined for p = 7 and for p = -7.
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Cheers,
Stan H.
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Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
this looks like:
(p^3-8p)/(p^2-49)

it looks like this equation would be undefined when p = + or - 7

that would make the denominator equal to 0 which would make the whole expression undefined.

i think that's it.

a graph of this equation can also help to show you where the undefined areas are.

It's not fool proof but it does help.

graph%28600%2C600%2C-40%2C40%2C-80%2C80%2C%28x%5E3+-+8x%29+%2F+%28x%5E2+-+49%29%29

in the graph above, if you draw a vertical line at x = -7 and at x = 7, you will see that the value is undefined at those points.

that's because the denominator of the equation is equal to 0 at those values of x.

in order to graph your equation, i had to change the "p" to an "x".

it doesn't change the equation.

it only changes the variable used.

this allows it to be graphed.