Identify the values of x that will make this rational expression \(x^{2}+2 x-15\)

(C) x = 3 or -5


The given rational expression is said to be undefined when the denominator \(x^{2}+2 x-15\) is equal to zero.
We first factor out the denominator: \(x^{2}+2 x-15=(x-3)(x+5)\).
Then we equate each of the factors to zero and get the values of x: x-3 = 0; x=3 x+5=0; x=-5.
Now we know that the given rational expression is undefined when x = 3 or -5.

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