On this week, we learned Rational Expressions and Equations. In these chapter, there are some new vocabulary. New words are rational expression, equivalent rational expressions, non permissible value rational equation, and rational equation. We have to know these words. In these words, the most important word is non permissible value. Non permissible value is rational expressions are not defined for values of the variable that make the denominator 0. These values are called non permissible values. Also in these chapter, we have to factor and find non permissible values.