# Identify the values of x that will make this rational expression $$x^{2}+2 x-15$$

(C) x = 3 or -5

Explanation

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.

Visit our website for other GED topics now!