document.write( "Question 259973: My book says the answer is -5 and -3, where am I missing it?
\n" ); document.write( "\"x%5E2-8x-15=0\"
\n" ); document.write( "x=\"%28-%28-8%29%2B-+sqrt%28-8%5E2-4%2A1%2A15%29%29%2F%282%2A1%29\"
\n" ); document.write( "x=\"8%2B-+sqrt+%2864-60%29%2F%282%29\"
\n" ); document.write( "x=\"8%2B-+sqrt+%284%29%2F%282%29\"
\n" ); document.write( "x=\"%288%2B2%29%2F%282%29=+10%2F2+=+5\"
\n" ); document.write( "x=\"%288-2%29%2F%282%29=+6%2F2+=3\"
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Algebra.Com's Answer #191419 by nerdybill(7384)\"\" \"About 
You can put this solution on YOUR website!
You are both wrong!
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\n" ); document.write( "Your mistake:
\n" ); document.write( "\"x%5E2-8x-15=0\"
\n" ); document.write( "x=\"%28-%28-8%29%2B-+sqrt%28-8%5E2-4%2A1%2A15%29%29%2F%282%2A1%29\" <--Here -- should be -15
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\n" ); document.write( "Unless your original equation has a typo then the quadratic equation yields:
\n" ); document.write( "x = {9.568, -1.568}
\n" ); document.write( "Details of quadratic equation follows:
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"ax%5E2%2Bbx%2Bc=0\" (in our case \"1x%5E2%2B-8x%2B-15+=+0\") has the following solutons:
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\n" ); document.write( " \"x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"
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\n" ); document.write( " For these solutions to exist, the discriminant \"b%5E2-4ac\" should not be a negative number.
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\n" ); document.write( " First, we need to compute the discriminant \"b%5E2-4ac\": \"b%5E2-4ac=%28-8%29%5E2-4%2A1%2A-15=124\".
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\n" ); document.write( " Discriminant d=124 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28--8%2B-sqrt%28+124+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"x%5B1%5D+=+%28-%28-8%29%2Bsqrt%28+124+%29%29%2F2%5C1+=+9.56776436283002\"
\n" ); document.write( " \"x%5B2%5D+=+%28-%28-8%29-sqrt%28+124+%29%29%2F2%5C1+=+-1.56776436283002\"
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\n" ); document.write( " Quadratic expression \"1x%5E2%2B-8x%2B-15\" can be factored:
\n" ); document.write( " \"1x%5E2%2B-8x%2B-15+=+1%28x-9.56776436283002%29%2A%28x--1.56776436283002%29\"
\n" ); document.write( " Again, the answer is: 9.56776436283002, -1.56776436283002.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-8%2Ax%2B-15+%29\"
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