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If you miss a problem, go back to the section listed and review the material.
To multiply rational expressions, we do just what we did with numerical fractions. We multiply the numerators and multiply the denominators. Then, if there are any common factors, we remove them to simplify the result.
If are polynomials where , then
To multiply rational expressions, multiply the numerators and multiply the denominators.
We’ll do the first example with numerical fractions to remind us of how we multiplied fractions without variables.
Multiply:
Multiply the numerators and denominators. | |
Look for common factors, and then remove them. | |
Simplify. |
Remember, throughout this chapter, we will assume that all numerical values that would make the denominator be zero are excluded. We will not write the restrictions for each rational expression, but keep in mind that the denominator can never be zero. So in this next example, and .
Mulitply:
Multiply. | |
Factor the numerator and denominator completely, and then remove common factors. | |
Simplify. |
Multiply:
Factor each numerator and denominator. | |
Multiply the numerators and denominators. | |
Remove common factors. | |
Simplify. |
To divide rational expressions we multiply the first fraction by the reciprocal of the second, just like we did for numerical fractions.
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