So we need to get the denominators of these two

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Unformatted text preview: r and cancel as much as we can. Here is the work for this part. 2 y 2 + 5 y + 4 ( y + 5 y + 4 ) ( y + 5 ) ( y + 1)( y + 4 )( y + 5 ) ( y + 4 )( y + 5 ) = = = y2 -1 y2 -1 y -1 ( y + 1)( y - 1) y+5 [Return to Problems] Okay, it’s time to move on to addition and subtraction of rational expressions. Here are the general formulas. a b a+b += cc c a b a-b -= cc c As these have shown we’ve got to remember that in order to add or subtract rational expression or fractions we MUST have common denominators. If we don’t have common denominators then we need to first get common denominators. Let’s remember how do to do this with a quick number example. 53 64 In this case we need a common denominator and recall that it’s usually best to use the least common denominator, often denoted lcd. In this case the least common denominator is 12. So we need to get the denominators of these two fractions to a 12. This is easy to do. In the first case we need to multiply the denominator by 2 to get 12 so we will multiply the numerator and denom...
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This note was uploaded on 06/06/2012 for the course ICT 4 taught by Professor Mrvinh during the Spring '12 term at Hanoi University of Technology.

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