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Unformatted text preview: e original rational expression. In this
case it is, LCD = ( x + 6 ) ( x - 3) Now, just look at each term and compare the denominator to the LCD. Multiply the numerator
and denominator by whatever is missing then add. In this case this gives, A ( x - 3)
B ( x + 6)
A ( x - 3) + B ( x + 6 )
8 x - 42
x + 3x - 18 ( x + 6 )( x - 3) ( x + 6 )( x - 3)
( x + 6 )( x - 3)
2 © 2007 Paul Dawkins 272 http://tutorial.math.lamar.edu/terms.aspx College Algebra We need values of A and B so that the numerator of the expression on the left is the same as the
numerator of the term on the right. Or, 8 x - 42 = A ( x - 3) + B ( x + 6 ) This needs to be true regardless of the x that we plug into this equation. As noted above there are
several ways to do this. One way will always work, but can be messy and will often require
knowledge that we don’t have yet. The other way will not always work, but when it does it will
greatly reduce the amount of work required.
In this set of examples the second (and easier) method will alw...
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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.
- Spring '12