document.write( "Question 1194297: Solve for x.\r
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Algebra.Com's Answer #826459 by ikleyn(52788) $\"\"$ $\"About$

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document.write( "Your starting equation is\r\n" );
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document.write( "    x^4 - 15x^2-16 = 0\r\n" );
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document.write( "It is so called biquadratic equation. To solve it, factor left side\r\n" );
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document.write( "    (x^2 - 16)*(x^2 + 1) = 0.\r\n" );
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document.write( "In real domain, it gives two solutions  x= 4 and x= -4.\r\n" );
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document.write( "In complex numbers, there are 4 possible solutions:  x= 4, x= -4, x= i =   and  x= -i = .\r\n" );
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