document.write( "Question 1181497: If -2 is a root of ((z^3) - (8(z^2)) + (9z) + 58 = 0, what are the other two roots? \n" ); document.write( "
Algebra.Com's Answer #811411 by ikleyn(52777)\"\" \"About 
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\n" ); document.write( "If -2 is a root of ((z^3) - (8(z^2)) + (9z) + 58 = 0, what are the other two roots?
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document.write( "In fact, -2 is a root of the given polynomial, and you can check it in one line, \r\n" );
document.write( "substituting the value of -2 into the polynomial\r\n" );
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document.write( "    \"%28-2%29%5E3\" - \"8%2A%28-2%29%5E2\" + \"9%2A%28-2%29\" + 58 = -8 - 32 - 18 + 58 = 0.\r\n" );
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document.write( "Therefore, the given polynomial is divisible by (z-2) without a remainer (according to the Remainder theorem)\r\n" );
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document.write( "and you can divide it using standard long division procedure \r\n" );
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document.write( "    \"%28z%5E3+-+8z%5E2+%2B+9z+%2B+58%29%2F%28z-2%29\" = z^2 - 10z + 29.\r\n" );
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document.write( "Solve this quadratic equation using the Quadratic Formula\r\n" );
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document.write( "    \"z%5B1%2C2%5D\" = \"%2810+%2B-+sqrt%2810%5E2+-+4%2A29%29%29%2F2\" = \"%2810+%2B-+sqrt%28-16%29%29%2F2\" = \"%2810+%2B-+4i%29%2F2\" = 5 +- 2i.\r\n" );
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document.write( "ANSWER.  Two other roots of the given equation are  (5+2i)  and  (5-2i).\r\n" );
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