document.write( "Question 549327: x^4-9x^2+20=0 \n" ); document.write( "

Algebra.Com's Answer #357773 by KMST(5328) $\"\"$ $\"About$

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If you changed variables to $\"y=x%5E2\"$
\n" ); document.write( "it would simplify into
\n" ); document.write( " $\"y%5E2-9y%2B20=0\"$ which you would factor to get $\"%28y-4%29%28y-5%29=0\"$ , so
\n" ); document.write( " $\"x%5E4-9x%5E2%2B20=0\"$ factors into $\"%28x%5E2-4%29%28x%5E2-5%29=0\"$
\n" ); document.write( "It further factors into
\n" ); document.write( " $\"%28x%2B2%29%28x-2%29%28x%2Bsqrt%285%29%29%28x-sqrt%285%29%29=0\"$
\n" ); document.write( "The 4 real solutions to that equation are:
\n" ); document.write( " $\"x=-2\"$ , $\"x=2\"$ , $\"x=-sqrt%285%29\"$ , and $\"x=sqrt%285%29\"$ \n" ); document.write( "

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