document.write( "Question 571216: Please help to solve this equation by completing the square:
\n" ); document.write( "3x^2 - x - 1 = 0 \n" ); document.write( "

Algebra.Com's Answer #368027 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"+3x%5E2+-+x+-+1+=+0+\"$
\n" ); document.write( " $\"+3x%5E2+-+x+=+1+\"$
\n" ); document.write( " $\"+x%5E2+-%281%2F3%29%2Ax+=+1%2F3+\"$
\n" ); document.write( "Take 1/2 of the coefficient of $\"x\"$ , square it
\n" ); document.write( "and add it to both sides
\n" ); document.write( " $\"+x%5E2+-%281%2F3%29%2Ax+%2B++%28-1%2F6%29%5E2+=+1%2F3++%2B+%28-1%2F6%29%5E2+\"$
\n" ); document.write( " $\"+x%5E2+-%281%2F3%29%2Ax+%2B+1%2F36+=+12%2F36+%2B+1%2F36+\"$
\n" ); document.write( " $\"+%28+x+-+1%2F6+%29%5E2+=+13%2F36+\"$
\n" ); document.write( "Take the square root of both sides
\n" ); document.write( " $\"+x+-+1%2F6+=+sqrt%28+13+%29+%2F+6+\"$
\n" ); document.write( " $\"+x+=+%28+1+%2B+sqrt%2813%29+%29+%2F+6+\"$
\n" ); document.write( "and, also
\n" ); document.write( " $\"+x+=+%28+1+-+sqrt%2813%29+%29+%2F+6+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( "check the solutions:
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\n" ); document.write( "Multiply both sides by $\"+12+\"$
\n" ); document.write( " $\"+1+-+2%2Asqrt%2813%29+%2B+13+-+2+%2B+2%2Asqrt%2813%29+-+12+=+0+\"$
\n" ); document.write( " $\"+1+%2B+13+-+2+-+12+=+0+\"$
\n" ); document.write( " $\"+0+=+0+\"$
\n" ); document.write( "OK. You can check other solution
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