Rational numbers are numbers that can be written as a fraction (quotient)Rational comes from ratio – a number is rational if it can be written as a ratio of two integers – ie a fraction!
A rationalexpression is an algebraicfractionThe ratio between two algebraic expressions (usually polynomials)
Factor theorem
In order to simplify a rational expression you'll need to remember the factor theorem
How to simplify a rational expression (algebraic fraction)
Start by factorising polynomials using factortheorem or algebraicdivision
cancel any common (linear) factors
recognise a top-heavy (improper) rational expression, simplify if needed