Determine what values makes this rational expression undefined x+1/x^2+2x-24

The expression ...

... (x+1)/(x²+2x-24)

will have a zero denominator when

... x² +2x -24 = 0

... (x +6)(x -4) = 0 . . . . . factored form

... x = -6, x = 4 . . . . . . . values of x that make the factors zero

The rational expression will be undefined when x = -6 or x = 4.