What Are Algebraic Fractions?
Algebraic fractions are fractions using a variable in the numerator or denominator, such as

. Because division by 0 is impossible, variables in the denominator have certain restrictions. The denominator can never equal 0. Therefore, in the fractions
Be aware of these types of restrictions.
Operations with Algebraic Fractions
Many techniques will simplify your work as you perform operations with algebraic fractions. As you review the examples, note the steps involved in each operation and any methods that will save you time.
Reducing algebraic fractions
To
reduce an algebraic fraction to lowest terms, first factor the numerator and the denominator; then
reduce, (or divide out) common factors.
Example 1
Reduce.
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Warning: Do not
reduce through an addition or subtraction sign as shown here.
Multiplying algebraic fractions
To
multiply algebraic fractions, first factor the numerators and denominators that are polynomials; then, reduce where possible. Multiply the remaining numerators together and denominators together. (If you've reduced properly, your answer will be in reduced form.)
Dividing algebraic fractions
To
divide algebraic fractions, invert the
second fraction and multiply. Remember, you can reduce only after you invert.
Example 3
Divide.
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Adding or subtracting algebraic fractions
To
add or
subtract algebraic fractions having a common denominator, simply keep the denominator and combine (add or subtract) the numerators. Reduce if possible.
Example 4
Perform the indicated operation.
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To
add or
subtract algebraic fractions having different denominators, first find a lowest common denominator (LCD), change each fraction to an equivalent fraction with the common denominator, and then combine each numerator. Reduce if possible.
Example 5
Perform the indicated operation.
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If there is a common variable factor with more than one exponent, use its greatest exponent.
Example 6
Perform the indicated operation.
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To find the lowest common denominator, it is often necessary to factor the denominators and proceed as follows.
Example 7
Perform the indicated operation.
Occasionally, a problem will require reducing what appears to be the final result. A problem like that is found in the next example.
Example 8
Perform the indicated operation.