document.write( "Question 122517: Find all real and imaginary solution to the equation.
\n" ); document.write( "b^4+13b^2+36=0 \n" ); document.write( "
Algebra.Com's Answer #89933 by solver91311(24713)\"\" \"About 
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document.write( "Let \"x=b%5E2\", then \"x%5E2=b%5E4\".\r\n" );
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document.write( "Substitute:\r\n" );
document.write( "\"b%5E4%2B13b%5E2%2B36=0\"\r\n" );
document.write( "\"x%5E2%2B13x%2B36=0\"\r\n" );
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document.write( "The quadratic factors:\r\n" );
document.write( "\"%28x%2B4%29%28x%2B9%29=0\"\r\n" );
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document.write( "Therefore\r\n" );
document.write( "\"x=-4\" or \"x=-9\"\r\n" );
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document.write( "But \"x=b%5E2\" so\r\n" );
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document.write( "\"b%5E2=-4\" or \"b%5E2=-9\"\r\n" );
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document.write( "Therefore\r\n" );
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document.write( "\"b=2i\"\r\n" );
document.write( "\"b=-2i\"\r\n" );
document.write( "\"b=3i\"\r\n" );
document.write( "\"b=-3i\"\r\n" );
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document.write( "Giving us the 4 expected roots for the quartic (degree 4) equation.\r\n" );
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document.write( "Since the roots are all complex, there are no real zeros for this equation,\r\n" );
document.write( "therefore the graph will not intercept the x-axis anywhere.\r\n" );
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document.write( "\"graph%28600%2C600%2C-5%2C5%2C-5%2C80%2Cx%5E4%2B13x%5E2%2B36%29\"\r\n" );
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