document.write( "Question 32359: ((( x^4 -x^2 -12 = 0)))) Can you please help me with this problems \n" ); document.write( "

Algebra.Com's Answer #18872 by Earlsdon(6294) $\"\"$ $\"About$

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Solve:
\n" ); document.write( " $\"x%5E4-x%5E2-12+=+0\"$ Rewrite this as a quadratic equation by temporarily substituting $\"y+=+x%5E2\"$ .
\n" ); document.write( " $\"y%5E2-y-12+=+0\"$ Solve by factoring.
\n" ); document.write( " $\"%28y%2B3%29%28y-4%29+=+0\"$ Apply the zero products principle.
\n" ); document.write( " $\"y%2B3+=+0\"$ and/or $\"y-4+=+0\"$
\n" ); document.write( "If $\"y%2B3+=+0\"$ then $\"y+=+-3\"$
\n" ); document.write( "If $\"y-4+=+0\"$ then $\"y+=+4\"$ \r
\n" ); document.write( "\n" ); document.write( "But, $\"y+=+x%5E2\"$ , so:\r
\n" ); document.write( "\n" ); document.write( " $\"x%5E2+=+-3\"$ Take the square root of both sides.
\n" ); document.write( " $\"x+=+sqrt%283%29i\"$ and $\"x+=+-sqrt%283%29i\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x%5E2+=+4\"$ Take the square root of both sides.
\n" ); document.write( " $\"x+=+2\"$ and $\"x+=+-2\"$ \r
\n" ); document.write( "\n" ); document.write( "The four roots are:
\n" ); document.write( " $\"x+=+sqrt%283%29i\"$
\n" ); document.write( " $\"x+=+-sqrt%283%29i\"$
\n" ); document.write( " $\"x+=+2\"$
\n" ); document.write( " $\"x+=+-2\"$ \n" ); document.write( "

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