document.write( "Question 1146530: How do you complete the square for $\"2x%5E2%2B2x-1\"$
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Algebra.Com's Answer #767801 by rothauserc(4718) $\"\"$ $\"About$

You can put this solution on YOUR website!
I assume you mean 2x^2 +2x -1 = 0, then
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\n" ); document.write( "2x^2 +2x = 1
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\n" ); document.write( "divide both sides of = by 2
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\n" ); document.write( "x^2 +x = 0.5
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\n" ); document.write( "x^2 +x +0.25 = 0.5 +0.25 = 0.75
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\n" ); document.write( "(x +0.5)^2 = 0.75
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\n" ); document.write( "take square root of both sides of =
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\n" ); document.write( "x +0.5 = + or -square root(0.75)
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\n" ); document.write( "Two solutions for x
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\n" ); document.write( "x = -0.5 +square root(0.75)
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\n" ); document.write( "x = -0.5 -square root(0.75)
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\n" ); document.write( "Note square root(0.75) = 0.5 * square root(3) = 0.866
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\n" ); document.write( "therefore the two solutions for x are
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\n" ); document.write( "x = 0.366 or x = -1.366
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\n" ); document.write( "check solutions by substituting for x in original equation
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\n" ); document.write( "2(0.366)^2 +2(0.366) -1 = 0
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\n" ); document.write( "0 = 0
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\n" ); document.write( "2(-1.366)^2 +2(-1.366) -1 = 0
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\n" ); document.write( "0 = 0
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\n" ); document.write( "answer checks for both values of x
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