document.write( "Question 918970: P(X)=x^3-3x^2-5x+10
\n" ); document.write( "A) Evaluate P(x) for integers -3 through 5
\n" ); document.write( "B) Find all of the zeros of P(x)
\n" ); document.write( "C) Prove that five is an upper bound on the zeros of P(X)
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Algebra.Com's Answer #557377 by MathLover1(20849)\"\" \"About 
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\n" ); document.write( "\"P%28X%29=x%5E3-3x%5E2-5x%2B10\"\r
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\n" ); document.write( "\n" ); document.write( "A) Evaluate \"P%28x%29\" for integers \"-3\" through \"5\":\r
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\n" ); document.write( "\n" ); document.write( "\"x=-3\"\r
\n" ); document.write( "\n" ); document.write( "\"%28-3%29%5E3-3%28-3%29%5E2-5%28-3%29%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"-27-27%2B15%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"-54%2B25\"\r
\n" ); document.write( "\n" ); document.write( "=\"-29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=-2\"\r
\n" ); document.write( "\n" ); document.write( "\"%28-2%29%5E3-3%28-2%29%5E2-5%28-2%29%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"-8-12%2B10%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"-20%2B20\"\r
\n" ); document.write( "\n" ); document.write( "=\"0\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=-1\"\r
\n" ); document.write( "\n" ); document.write( "\"%28-1%29%5E3-3%28-1%29%5E2-5%28-1%29%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"-1-3%2B5%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"-4%2B15\"\r
\n" ); document.write( "\n" ); document.write( "=\"11\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%280%29%5E3-3%280%29%5E2-5%280%29%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"0-0%2B0%2B10\"\r
\n" ); document.write( "\n" ); document.write( "=\"10\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=1\"\r
\n" ); document.write( "\n" ); document.write( "\"%281%29%5E3-3%281%29%5E2-5%281%29%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"1-3-5%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"-8%2B11\"\r
\n" ); document.write( "\n" ); document.write( "=\"3\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=2\"\r
\n" ); document.write( "\n" ); document.write( "\"%282%29%5E3-3%282%29%5E2-5%282%29%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"8-12-10%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"-22%2B18\"\r
\n" ); document.write( "\n" ); document.write( "=\"-4\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=3\"\r
\n" ); document.write( "\n" ); document.write( "\"%283%29%5E3-3%283%29%5E2-5%283%29%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"27-27-15%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"0-15%2B10\"\r
\n" ); document.write( "\n" ); document.write( "=\"-5\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=4\"\r
\n" ); document.write( "\n" ); document.write( "\"%284%29%5E3-3%284%29%5E2-5%284%29%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"64-48-20%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"74-68\"\r
\n" ); document.write( "\n" ); document.write( "=\"6\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=5\"\r
\n" ); document.write( "\n" ); document.write( "\"%285%29%5E3-3%285%29%5E2-5%285%29%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"125-75-25%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"135-100\"\r
\n" ); document.write( "\n" ); document.write( "=\"35\"\r
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\n" ); document.write( "\n" ); document.write( "B) Find all of the zeros of \"P%28x%29\"\r
\n" ); document.write( "\n" ); document.write( "\"P%28X%29=x%5E3-3x%5E2-5x%2B10\"\r
\n" ); document.write( "\n" ); document.write( "\"x%5E3-3x%5E2-5x%2B10=0\"\r
\n" ); document.write( "\n" ); document.write( "\"x%5E3-5x%5E2%2B5x%2B2x%5E2-10x%2B10=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28x%5E3%2B2x%5E2%29-%285x%5E2%2B10x%29%2B%285x%2B10%29=0\"\r
\n" ); document.write( "\n" ); document.write( "\"x%5E2%28x%2B2%29-5x%28x%2B2%29%2B5%28x%2B2%29=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28x%2B2%29%28x%5E2-5x%2B5%29+=+0\"\r
\n" ); document.write( "\n" ); document.write( "one zero is:\r
\n" ); document.write( "\n" ); document.write( "\"%28x%2B2%29+=+0\"=>\"highlight%28x=-2%29\"\r
\n" ); document.write( "\n" ); document.write( "\"x%5E2-5x%2B5+=+0\" ...use quadratic formula to find other two zeros:\r
\n" ); document.write( "\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\" \r
\n" ); document.write( "\n" ); document.write( "\"x+=+%28-%28-5%29+%2B-+sqrt%28+%28-5%29%5E2-4%2A1%2A5+%29%29%2F%282%2A1%29+\" \r
\n" ); document.write( "\n" ); document.write( "\"x+=+%285+%2B-+sqrt%28+25-20+%29%29%2F2+\" \r
\n" ); document.write( "\n" ); document.write( "\"x+=+%285+%2B-+sqrt%28+5+%29%29%2F2+\" \r
\n" ); document.write( "\n" ); document.write( "\"x+=+%285+%2B-+2.236%29%2F2+\"\r
\n" ); document.write( "\n" ); document.write( "solutions:\r
\n" ); document.write( "\n" ); document.write( "\"x+=+%285+%2B+2.236%29%2F2+\"\r
\n" ); document.write( "\n" ); document.write( "\"x+=+7.236%2F2+\"\r
\n" ); document.write( "\n" ); document.write( "\"x+=3.6\"\r
\n" ); document.write( "\n" ); document.write( "and\r
\n" ); document.write( "\n" ); document.write( "\"x+=+%285+-+2.236%29%2F2+\"\r
\n" ); document.write( "\n" ); document.write( "\"x+=+2.764%2F2+\"\r
\n" ); document.write( "\n" ); document.write( "\"x+=1.4\"\r
\n" ); document.write( "\n" ); document.write( "so, zeros are:\"highlight%28x=-2%29\",\"highlight%28x=3.6%29\", and \"highlight%28x=1.4%29\"\r
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\n" ); document.write( "\n" ); document.write( "C) Prove that five is an upper bound on the zeros of \"P%28X%29\"\r
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\n" ); document.write( "\n" ); document.write( "to find bounds for the real roots of the polynomial means we are looking for a number that is greater than all roots (an upper bound) and a number that is less than all roots (a lower bound) \r
\n" ); document.write( "\n" ); document.write( "we are looking if \"5\" is greater than all roots
\n" ); document.write( "zeros are:
\n" ); document.write( "\"5%3Ehighlight%28-2%29\",
\n" ); document.write( "\"5%3Ehighlight%283.6%29\", and
\n" ); document.write( "\"5%3Ehighlight%281.4%29\"\r
\n" ); document.write( "\n" ); document.write( "so, it's proven that \"5\" is an upper bound on the zeros of \"P%28X%29\"\r
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\n" ); document.write( "\n" ); document.write( "graph of \"P%28X%29\":\r
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\n" ); document.write( "\n" ); document.write( "\"+graph%28+600%2C+600%2C+-20%2C+20%2C+-20%2C+20%2C+x%5E3-3x%5E2-5x%2B10%29+\" \r
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