document.write( "Question 66792: Solve by completing the square.
\n" ); document.write( "2x^2-12x-18=0
\n" ); document.write( "How do you do it. Thanks \n" ); document.write( "

Algebra.Com's Answer #47490 by Earlsdon(6294) $\"\"$ $\"About$

You can put this solution on YOUR website!
Solve by completing the square:
\n" ); document.write( " $\"2x%5E2-12x-18+=+0\"$ First, you want to get the coefficient of the $\"x%5E2\"$ term to be 1, so divide everything by 2.
\n" ); document.write( " $\"%282x%5E2-12x-18%29%2F2+=+0%2F2\"$ Simplify.
\n" ); document.write( " $\"x%5E2-6x-9+=+0\"$ Now move the constant term (-9) to the right side of the equation by adding 9 to both sides.
\n" ); document.write( " $\"x%5E2-6x+=+9\"$ Next, add the square of half the x-coefficient $\"%28%28-6%29%2F2%29%5E2+=+%28-3%29%5E2\"$ = 9 to both sides.
\n" ); document.write( " $\"x%5E2-6x%2B9+=+18\"$ Now factor the left side.
\n" ); document.write( " $\"%28x-3%29%5E2+=+18\"$ Take the square root of both sides.
\n" ); document.write( " $\"x-3+\"$ = +/- $\"sqrt%2818%29\"$ Add 3 to both sides.
\n" ); document.write( " $\"x+=+3%2B-sqrt%2818%29\"$ Simplify. Note that: $\"sqrt%2818%29+=+sqrt%289%2A2%29\"$ = $\"3sqrt%282%29\"$
\n" ); document.write( " $\"x1+=+3%2B3sqrt%282%29\"$
\n" ); document.write( " $\"x2+=+3-3sqrt%282%29\"$ \n" ); document.write( "

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