Combining rational expression with unlike denominators

The video tutorial explains how to subtract two rational fractions by first ensuring common denominators. It covers simplifying denominators through factoring, finding the least common denominator, and combining fractions. The tutorial concludes with setting restrictions by solving for values that make the denominator zero, emphasizing the importance of these restrictions in rational expressions.

Explain the process of simplifying the denominators in the given problem.

What does it mean when we say that X cannot equal certain values?