document.write( "Question 118101: The degree three polynomial f(x) with real coefficients and leading coefficient 1, has -3 and +4i among its roots. Express f(x) as a product of linear and quadratic polynomials with real coefficients. \n" ); document.write( "
Algebra.Com's Answer #86191 by jim_thompson5910(35256)\"\" \"About 
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Remember, if a polynomial has roots of a and b, then it's factorization will be \"%28x-a%29%28x-b%29\"\r
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\n" ); document.write( "\n" ); document.write( "So if a polynomial has roots of -3, 4i, and -4i (remember complex roots always come in pairs) , then it's factorization will be \r
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\n" ); document.write( "\n" ); document.write( "\"%28x-%28-3%29%29%28x-4i%29%28x-%28-4i%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B3%29%28x-4i%29%28x%2B4i%29\" Rewrite \"x-%28-3%29\" as \"x%2B3\" and \"x-%28-4i%29\" as \"x%2B4i\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B3%29%28x%5E2%2B4xi-4xi-4i%5E2%29\" Foil \"%28x-4i%29%28x%2B4i%29\" to get \"x%5E2%2B4xi-4xi-4i%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B3%29%28x%5E2-16i%5E2%29\" Combine like terms\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B3%29%28x%5E2-16%28-1%29%29\" Replace \"i%5E2\" with -1\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B3%29%28x%5E2%2B16%29\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E3%2B3x%5E2%2B16x%2B48\" Now foil \"%28x%2B3%29%28x%5E2%2B16%29\" to get \"x%5E3%2B3x%5E2%2B16x%2B48\"\r
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\n" ); document.write( "\n" ); document.write( "So the polynomial with roots of -3 and +4i is \"x%5E3%2B3x%5E2%2B16x%2B48\"
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