document.write( "Question 1180054: What number should be added to the equation 2 x squared plus 8 x minus 5 equals 0 if you will use completing the square?
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Algebra.Com's Answer #809663 by greenestamps(13203) $\"\"$ $\"About$

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\n" ); document.write( "The problem is poorly worded, so we don't really know what the question is that they are asking.

\n" ); document.write( "To begin with, you can't add a number to an equation without changing the equation. What you CAN do is add the SAME number to BOTH SIDES of an equation.

\n" ); document.write( "To complete a square, you need to factor out the coefficient of the leading term and then use the pattern

\n" ); document.write( " $\"%28x%2Ba%29%5E2+=+x%5E2%2B2ax%2Ba%5E2\"$

\n" ); document.write( " $\"2x%5E2%2B8x-5=0\"$
\n" ); document.write( " $\"2x%5E2%2B8x=-5\"$
\n" ); document.write( " $\"2%28x%5E2%2B4x%29=-5\"$

\n" ); document.write( "Using the pattern above, we have to add \"+4\" inside the parentheses. The expression in parentheses is being multiplied by 2, so we are adding 8 to the left side of the equation. So we can add 8 to BOTH SIDES of the equation to complete the square.

\n" ); document.write( " $\"2%28x%5E2%2B4x%2B4%29=-5%2B8\"$
\n" ); document.write( " $\"2%28x%2B2%29%5E2=3\"$

\n" ); document.write( "So with my interpretation of the question, the number I added TO BOTH SIDES OF THE EQUATION was 8.

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