Algebraic fractions, also known as rational expressions, are fractions containing variables.

Algebraic fractions should be cancelled down whenever possible.

Simplifying by Factorising

Fractions involving algebraic expressions can often be simplified using factorising and cancelling.

e.g. Y11_Algebraic_Fractions_01.gif

 

Algebraic fractions can be added, subtracted, multiplied or divided.

Multiplying Algebraic Fractions

Cancel where possible and then multiply numerators and denominators separately.

e.g. Y11_Algebraic_Fractions_02.gif

Dividing Algebraic Fractions

Turn second fraction upside down and multiply then cancel where possible and then multiply numerators and denominators separately.

e.g. Y11_Algebraic_Fractions_03.gif

Adding and Subtracting Algebraic Fractions

With all problems involving adding and subtracting algebraic fractions the fractions must have acommon denominator, just the same as number fractions.

Examples of adding and subtracting algebraic fractions:

Sometimes the denominators are already the same. Y11_Algebraic_Fractions_04.gif
Sometimes they are easy. Y11_Algebraic_Fractions_05.gif
Sometimes they are not so easy! Y11_Algebraic_Fractions_06.gif