For what values of x would the rational expression be undefined? x+3/x^2-x-12

Answer 1

4 and -3

factor the denominator

(x+3)/(x^2-x-12) = (x+3)/(x-4)(x+3)

the denominator cannot = 0

x=4 and x=-3 make the denominator zero

That assumes you had implicit parentheses

Otherwise, the way it reads is (x^3/x^2) -x -12

then x=0 would make it undefined

Answer 2

Since division by zero is undefined, a rational expression will also be undefined whenever its denominator equals zero. So set the denominator equal to zero and solve for the values of x.

x² - x - 12 = 0

This equation can be solved by factoring. You'll get two answers. The rational expression will be undefined at both values of x.