How to Rationalize a Denominator, Exponent Expressions and Equations, Algebra I

"Sal, why do we care? Why must we rationalize denominators?" Acknowledging these (possibly pleading) concerns, Sal explains the reasons behind rationalizing a denominator before demonstrating how to do it several times. Though he admits that one reason could be for "aesthetics," Sal contends that the process is essential to learn and understand.