document.write( "Question 305990: When working on finding the zeros on f(x)=x(x2-8x-2) how do I even start? I\"m very lost. I have look at the examples given in my text book, but can't make sense of it. \n" ); document.write( "

Algebra.Com's Answer #219042 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"f%28x%29+=+x%2A%28x%5E2+-+8x+-+2%29\"$
\n" ); document.write( "What values of $\"x\"$ make $\"f%28x%29+=+0\"$ ?
\n" ); document.write( "One solution is obviously $\"x+=+0\"$
\n" ); document.write( "because $\"f%280%29+=+0%2A%28-2%29+=+0\"$
\n" ); document.write( "Then find the zeros of
\n" ); document.write( " $\"x%5E2+-+8x+-+2+=+0\"$
\n" ); document.write( "I'll solve by completing the square
\n" ); document.write( " $\"x%5E2+-+8x+%2B+%288%2F2%29%5E2+=+%288%2F2%29%5E2+%2B+2\"$
\n" ); document.write( " $\"x%5E2+-+8x+%2B+16+=+16+%2B+2\"$
\n" ); document.write( " $\"%28x+-+4%29%5E2+=+18\"$
\n" ); document.write( " $\"x+-+4+=+sqrt%2818%29\"$
\n" ); document.write( " $\"x+-+4+=+3%2Asqrt%282%29\"$
\n" ); document.write( " $\"x+=+4+%2B-+3%2Asqrt%282%29\"$
\n" ); document.write( "It looks like the zeros are:
\n" ); document.write( " $\"x+=+0\"$
\n" ); document.write( " $\"x+=+4+%2B+3%2Asqrt%282%29\"$
\n" ); document.write( " $\"x+=+4+-+3%2Asqrt%282%29\"$ \n" ); document.write( "

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