document.write( "Question 131936: Factoring Polynomials -\r
\n" ); document.write( "\n" ); document.write( "Please factor the following:\r
\n" ); document.write( "\n" ); document.write( "w4 - 8w2 - 9
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Algebra.Com's Answer #96317 by solver91311(24713)\"\" \"About 
You can put this solution on YOUR website!
I presume you meant \"w%5E4+-+8w%5E2+-+9\"\r
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\n" ); document.write( "\n" ); document.write( "Let \"x=w%5E2\", then substitute:\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2-8x-9\"\r
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\n" ); document.write( "\n" ); document.write( "\"-9%2A1=-9\" and \"-9%2B1=-8\", so the factors of \"x%5E2-8x-9\" are:\r
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\n" ); document.write( "\n" ); document.write( "\"%28x-9%29%28x%2B1%29\"\r
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\n" ); document.write( "\n" ); document.write( "but \"x=w%5E2\", so two of the factors of \"w%5E4+-+8w%5E2+-+9\" are:\r
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\n" ); document.write( "\n" ); document.write( "\"%28w%5E2-9%29%28w%5E2%2B1%29\"\r
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\n" ); document.write( "\n" ); document.write( "The first of these factors is the difference of two squares and factors directly to:\r
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\n" ); document.write( "\n" ); document.write( "\"%28w%5E2-9%29=%28w-3%29%28w%2B3%29\"\r
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\n" ); document.write( "\n" ); document.write( "For the other factor, we need to use the fact that \"a\" is a zero of a single variable polynomial in x if and only if \"x-a\" is a factor of the polynomial.\r
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\n" ); document.write( "\n" ); document.write( "So, solve \"w%5E2%2B1=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"w%5E2=-1\" => \"w+=+i\" or \"w+=+-i\" where \"i%5E2=-1\", therefore the two factors of \"w%5E2%2B1\" are \"%28w-i%29%28w%2Bi%29\"\r
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\n" ); document.write( "\n" ); document.write( "In summary:
\n" ); document.write( "\"w%5E4+-+8w%5E2+-+9=%28w-3%29%28w%2B3%29%28w-i%29%28w%2Bi%29\"\r
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\n" ); document.write( "\n" ); document.write( "If you were only supposed to factor over the real numbers, then your answer would be:
\n" ); document.write( "\"w%5E4+-+8w%5E2+-+9=%28w-3%29%28w%2B3%29%28w%5E2%2B1%29\"
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