Rational expressions (and equations) involve ratios of polynomials. The root word of rational is "ratio" for that reason.
Rational expressions can be simplified by canceling out of common factors in the numerator and denominator. For that reason, factoring is an essential skill needed. Excluded values are values that a variable CANNOT be because it would cause an expression to be dividing by zero.
Solving rational equations is using general understanding of solving equations. Rational equations can be used to model numerous real world applications.

