# Simplify rational expressions: common binomial factors

Factor the numerator and the denominator of a rational expression and cancel out common binomial terms.

### Problem

Simplify the following rational expression.
start fraction, k, start superscript, 2, end superscript, minus, 22, k, plus, 121, divided by, k, start superscript, 2, end superscript, minus, 121, end fraction, equals
Which values of k make the expression undefined?
Select all that apply.
Select all that apply.