Day 18 – Addition & Subtraction of Rational Expressions

TEXT: Intermediate Algebra by Miller, O’Neill & Hyde

Videos from Khan Academy.

Day 18 – Addition & Subtraction of Rational Expressions

We can easily add or subtract 2 rational expressions that have the same denominator using one of the following:

If the denominators are not the same, then find the Least Common Multiple (LCM) of the Denominators, better known as the Least Common Denominator (LCD):

Once the LCD is found then you must multiply the numerator and denominator of a particular fraction by whatever factors are needed to get the denominator to be the common one. Once the denominators are the same, then proceed as before:

Two examples adding 2 rational expressions with monomial denominators:

An example subtracting 2 rational expressions with monomial denominators:

One example with more general denominators:

2 Responses to Day 18 – Addition & Subtraction of Rational Expressions

  1. No Matter how much i pratice its like i have to keep going back to my notes to compare with the homework i wish there was an easier way to remember the difference between mutiply divide and subtract its very confusing

  2. awiltshire says:

    Pro. halleck

    So I’m gonna watch the videos, see if I get it

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