document.write( "Question 61072: 3x^-2-27x^-1+42=0
\n" ); document.write( "I need help solving for u and back substituting for x. I would appreciate your help. Thanks \n" ); document.write( "

Algebra.Com's Answer #41992 by Earlsdon(6294) $\"\"$ $\"About$

You can put this solution on YOUR website!
You can temporarily substitute u for $\"x%5E%28-1%29\"$ , so rewriting the equation:
\n" ); document.write( " $\"3u%5E2+-+27u+%2B+42+=+0\"$ Start by factoring a 3.
\n" ); document.write( " $\"3%28u%5E2+-+9u+%2B+14%29+=+0\"$ Aplying the zero product principle:
\n" ); document.write( " $\"u%5E2+-+9u+%2B+14+=+0\"$ Factor the the left side:
\n" ); document.write( " $\"%28u+-+2%29%28u+-+7%29+=+0\"$ Apply the zero product principle:
\n" ); document.write( " $\"u+-+2+=+0\"$ and/or $\"u+-+7+=+0\"$ \r
\n" ); document.write( "\n" ); document.write( "u = 2 and/or u = 7 Now replace the $\"x%5E%28-1%29\"$ for u.\r
\n" ); document.write( "\n" ); document.write( " $\"x%5E%28-1%29+=+2\"$
\n" ); document.write( " $\"1%2Fx+=+2\"$
\n" ); document.write( " $\"1+=+2x\"$
\n" ); document.write( " $\"x+=+1%2F2\"$
\n" ); document.write( "---
\n" ); document.write( " $\"x%5E%28-1%29+=+7\"$
\n" ); document.write( " $\"1%2Fx+=+7\"$
\n" ); document.write( " $\"1+=+7x\"$
\n" ); document.write( " $\"x+=+1%2F7\"$ \n" ); document.write( "

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