Rational Expressions

Factor, cancel common factors, and watch for values that make a denominator zero.

Factor the numerator and denominator before canceling.
To add, find a common denominator.
To solve an equation with fractions, multiply every term by the common denominator.
Exclude values that make a denominator zero.

Watch out: Canceling terms instead of factors.

Worked example

Simplify (x² − 9)/(x − 3), for x ≠ 3.

Answer: x + 3

Try it yourself

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