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Part of video series Rational Expressions
Taught by MrLovellFord

### Meets NCTM Standards:

When adding rational expressions that are in fractional form, the trick is to rewrite those expressions so that they have common denominators. One of the denominators may already have a factor of the other term so you only have to multiply one of the terms by one of the factors in order to get a common denominator. Once you have common denominators, then simplify numerators and combine like terms if possible. Further factoring might or might not be possible.
• How do you add 2 rational expressions?
• How do you add (x + 5)/(x + 3) + (-12x - 4)/(x^2 - 4x - 21)?
This lesson goes through a rather complicated example of adding 2 rational expressions with different denominators. One denominator is a simple binomial while the other is a quadratic expression. This problem requires factoring, finding common denominators, and adding expressions. All steps are explained very well.
• Currently 4.0/5 Stars.
Reviewed by MathVids Staff on June 01, 2010.  