document.write( "Question 1160754: Check that (2+i) is a root of z^4+2(z^3)-9(z^2)-10z+50=0. Find the remaining three roots. \n" ); document.write( "
Algebra.Com's Answer #784150 by MathLover1(20850)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "\"z%5E4%2B2z%5E3-9z%5E2-10z%2B50=0\" factor\r
\n" ); document.write( "\n" ); document.write( "\"z%5E4%2B+6z%5E3+%2B10z%5E2+-4z%5E3-24z%5E2-40z+%2B5z%5E2%2B30z+%2B50=0\" group\r
\n" ); document.write( "\n" ); document.write( "\"%28z%5E4-4z%5E3%2B5z%5E2%29%2B+%286z%5E3-24z%5E2%2B30z%29%2B%2810z%5E2-40z+%2B50%29=0\"\r
\n" ); document.write( "\n" ); document.write( "\"z%5E2%28z%5E2-4z%2B5%29%2B+6z%28z%5E2-4z%2B5%29%2B10%28z%5E2-4z+%2B5%29=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28z%5E2+-+4+z+%2B+5%29+%28z%5E2+%2B+6+z+%2B+10%29+=+0\"\r
\n" ); document.write( "\n" ); document.write( "use quadratic function to find roots\r
\n" ); document.write( "\n" ); document.write( "for \"%28z%5E2+-+4+z+%2B+5%29=0\"\r
\n" ); document.write( "\n" ); document.write( "\"z=%28-%28-4%29%2B-sqrt%28%28-4%29%5E2-4%2A1%2A5%29%29%2F%282%2A1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"z=%284%2B-sqrt%2816-20%29%29%2F2\"\r
\n" ); document.write( "\n" ); document.write( "\"z=%284%2B-sqrt%28-4%29%29%2F2\"\r
\n" ); document.write( "\n" ); document.write( "\"z=%284%2B-2i%29%2F2\"\r
\n" ); document.write( "\n" ); document.write( "\"z=%282%2B-i%29\"\r
\n" ); document.write( "\n" ); document.write( "roots are: \r
\n" ); document.write( "\n" ); document.write( "\"z=2%2Bi\" ->is a root of \"z%5E4%2B2z%5E3-9z%5E2-10z%2B50=0\"\r
\n" ); document.write( "\n" ); document.write( "since complex roots always come in pairs, you also have \"z=2-i\"\r
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\n" ); document.write( "\n" ); document.write( "and remaining roots are:\r
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\n" ); document.write( " for\"+%28z%5E2+%2B+6+z+%2B+10%29+=+0\"\r
\n" ); document.write( "\n" ); document.write( "\"z=%28-6%2B-sqrt%286%5E2-4%2A1%2A10%29%29%2F%282%2A1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"z=%28-6%2B-sqrt%2836-40%29%29%2F2\"\r
\n" ); document.write( "\n" ); document.write( "\"z=%28-6%2B-sqrt%28-4%29%29%2F2\"\r
\n" ); document.write( "\n" ); document.write( "\"z=%28-6%2B-2i%29%2F2\"\r
\n" ); document.write( "\n" ); document.write( "\"z=%28-3%2B-i%29\"\r
\n" ); document.write( "\n" ); document.write( "roots are: \r
\n" ); document.write( "\n" ); document.write( "\"z=-3%2Bi\"
\n" ); document.write( "\"z=-3-i\" \r
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