document.write( "Question 441646: solve this quadratic equation\r
\n" ); document.write( "\n" ); document.write( "x^4-5x^2+4=0 \n" ); document.write( "
Algebra.Com's Answer #304775 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
x^4-5x^2+4=0
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\n" ); document.write( "Factor:
\n" ); document.write( "(x^2-4)(x^2-1) = 0
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\n" ); document.write( "(x-2)(x+2)(x-1)(x+1) = 0
\n" ); document.write( "x = -2 or -1 or 1 or +2
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\n" ); document.write( "If you use a \"u-substitution\" you get:
\n" ); document.write( "Let u = x^2
\n" ); document.write( "Then u^2-5u+4 = 0
\n" ); document.write( "Factor:
\n" ); document.write( "(u-4)(u-1) = 0
\n" ); document.write( "u = 4 or u = 1
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\n" ); document.write( "Convert to \"x\" solutions:
\n" ); document.write( "x^2 = 4 or x^2 = 1
\n" ); document.write( "x = +/- 2 or x = +/-1
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\n" ); document.write( "\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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