Here's how you'll do it:
1. Check the expression itself; if it's factorable, factor it first on the numerator, then denominator.
2. Find its numeral coefficients. See if they had GCF and divide it by that number.
3. Check the variables. See if they're the same, applying the Rule of Exponents for Division.
4. Cross out any common factors between the two parts of fraction.
