document.write( "Question 830419: How do I find all of the roots for x to the 4- 6x squared plus 7 \n" ); document.write( "

Algebra.Com's Answer #500825 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
Substitute $\"u=x%5E2\"$
\n" ); document.write( " $\"x%5E4-6x%5E2%2B7=0\"$
\n" ); document.write( " $\"u%5E2-6u%2B7=0\"$
\n" ); document.write( " $\"%28u-7%29%28u%2B1%29=0\"$
\n" ); document.write( "Now back substitute,
\n" ); document.write( " $\"u-7=0\"$
\n" ); document.write( " $\"x%5E2-7=0\"$
\n" ); document.write( " $\"x=sqrt%287%29\"$ and $\"x=-sqrt%287%29\"$
\n" ); document.write( ".
\n" ); document.write( ".
\n" ); document.write( " $\"u%2B1=0\"$
\n" ); document.write( " $\"u=-1\"$
\n" ); document.write( " $\"x%5E2=-1\"$
\n" ); document.write( " $\"x=i\"$ and $\"x=-i\"$ \r
\n" ); document.write( "
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