document.write( "Question 22: This is a basic question but I can seem to explain it. The Quadratic Equation term \"b^2 -4ab\" why do we change it to \"b^2+ 4ab\" when the \"b\" value is negative? Thanks annmrj@aol.com\r
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Algebra.Com's Answer #9 by AnlytcPhil(1806) $\"\"$ $\"About$

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This is a basic question but I can seem to explain it.
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document.write( "The Quadratic Equation term \"b^2 -4ab\" why do we change 
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document.write( "it to \"b^2+ 4ab\" when the \"b\" value is negative?
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document.write( "We don't. First of all it's not b²-4ab, it's b²-4ac. 
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document.write( "Also your example:
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document.write( "b^2-4ab (x^2-6x-27=0) = 6^2+4(1)(-27)=144 
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document.write( "is incorrect in the next to last step, although 144 is correct.
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document.write( "It should be
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document.write( "b^2-4ab (x^2-6x-27=0) = 6^2-4(1)(-27)=144 
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document.write( "What you have there, namely,
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document.write( "6^2+4(1)(-27)=
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document.write( "equals to -72, not 144.\r
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document.write( "Suppose we have
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document.write( "     2x² + 5x - 3
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document.write( "then a=2, b=5, and c=-3
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document.write( "So
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document.write( "     b² - 4ac
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document.write( "becomes
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document.write( "     (5)² - 4(2)(-3)
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document.write( "or
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document.write( "     25 - (-24)
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document.write( "and then the \" - \" sign before the parentheses and the \" - \"  
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document.write( "before the 24 inside the parentheses becomes a \" + \", and we
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document.write( "have
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document.write( "    25 + 24
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document.write( "or
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document.write( "    49 \r
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document.write( "Edwin 
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