## Introductory Algebra for College Students (7th Edition)

$\displaystyle \frac{1}{x+4},\qquad\frac{x^{2}+1}{x+4}...$ (sample answers)
A rational expression is undefined at any value that produces a denominator of 0. So, place a polynomial such as $(x+4)$ as a factor of the denominator.... $\displaystyle \frac{1}{x+4},\qquad\frac{x^{2}+1}{x+4}...$ (sample answers)