document.write( "Question 481460: I need help with this problem.
\n" ); document.write( "solve x^4+10x^2+9=0
\n" ); document.write( "Thank you! \n" ); document.write( "

Algebra.Com's Answer #329669 by Earlsdon(6294) $\"\"$ $\"About$

You can put this solution on YOUR website!
You can use a temporary substitution in which $\"z+=+x%5E2\"$ , so...
\n" ); document.write( " $\"x%5E4%2B10x%5E2%2B9+=+0\"$ Substitute $\"z+=+x%5E2\"$
\n" ); document.write( " $\"z%5E2%2B10z%2B9+=+0\"$ Factor.
\n" ); document.write( " $\"%28z%2B1%29%28z%2B9%29+=+0\"$ Apply the \"zero product\" rule.
\n" ); document.write( " $\"z%2B1+=+0\"$ or $\"z%2B9+=+0\"$ so that...
\n" ); document.write( " $\"z+=+-1\"$ or $\"z+=+-9\"$ Now replace the temporary variable z with $\"z+=+x%5E2\"$ to get:
\n" ); document.write( " $\"x%5E2+=+-1\"$ or $\"x%5E2+=+-9\"$ and so...
\n" ); document.write( " $\"x+=+sqrt%28-1%29\"$ , $\"x+=+-sqrt%28-1%29\"$ , or $\"x+=+sqrt%28-9%29\"$ , $\"x+=+-sqrt%28-9%29\"$ But these can be simplified to...
\n" ); document.write( " $\"x+=+i\"$ , $\"x+=+-i\"$ or $\"x+=+3i\"$ , $\"x+=+-3i\"$ where $\"i+=+sqrt%28-1%29\"$ \n" ); document.write( "

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