document.write( "Question 177853: Solve by completing the square. Show your work.[please]\r
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\n" ); document.write( "\n" ); document.write( "29. 2x2 - 6x + 1 = 0\r
\n" ); document.write( "\n" ); document.write( " 30. -x2 - 8x + 5 = 0\r
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\n" ); document.write( "\n" ); document.write( "31. 9x2 - 18x - 1 = 0\r
\n" ); document.write( "\n" ); document.write( " 32. -4x2 + 8x - 3 = 0
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Algebra.Com's Answer #132878 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
I'll do the first two to get you started\r
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\n" ); document.write( "\n" ); document.write( "\"2x%5E2-6x%2B1\" Start with the given expression.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%5E2-3x%2B1%2F2%29\" Factor out the \"x%5E2\" coefficient \"2\". This step is very important: the \"x%5E2\" coefficient must be equal to 1.\r
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\n" ); document.write( "\n" ); document.write( "Take half of the \"x\" coefficient \"-3\" to get \"-3%2F2\". In other words, \"%281%2F2%29%28-3%29=-3%2F2\".\r
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\n" ); document.write( "\n" ); document.write( "Now square \"-3%2F2\" to get \"9%2F4\". In other words, \"%28-3%2F2%29%5E2=%28-3%2F2%29%28-3%2F2%29=9%2F4\"\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%5E2-3x%2Bhighlight%289%2F4-9%2F4%29%2B1%2F2%29\" Now add and subtract \"9%2F4\" inside the parenthesis. Make sure to place this after the \"x\" term. Notice how \"9%2F4-9%2F4=0\". So the expression is not changed.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x%5E2-3x%2B9%2F4%29-9%2F4%2B1%2F2%29\" Group the first three terms.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x-3%2F2%29%5E2-9%2F4%2B1%2F2%29\" Factor \"x%5E2-3x%2B9%2F4\" to get \"%28x-3%2F2%29%5E2\".\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x-3%2F2%29%5E2-7%2F4%29\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-3%2F2%29%5E2%2B2%28-7%2F4%29\" Distribute.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-3%2F2%29%5E2-7%2F2\" Multiply.\r
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\n" ); document.write( "\n" ); document.write( "So after completing the square, \"2x%5E2-6x%2B1\" transforms to \"2%28x-3%2F2%29%5E2-7%2F2\". So \"2x%5E2-6x%2B1=2%28x-3%2F2%29%5E2-7%2F2\".\r
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\n" ); document.write( "\n" ); document.write( "So \"2x%5E2-6x%2B1=0\" is equivalent to \"2%28x-3%2F2%29%5E2-7%2F2=0\".\r
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\n" ); document.write( "\n" ); document.write( "Now let's solve \"2%28x-3%2F2%29%5E2-7%2F2=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-3%2F2%29%5E2-7%2F2=0\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-3%2F2%29%5E2=0%2B7%2F2\"Add \"7%2F2\" to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-3%2F2%29%5E2=7%2F2\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"%28x-3%2F2%29%5E2=%287%2F2%29%2F%282%29\" Divide both sides by \"2\".\r
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\n" ); document.write( "\n" ); document.write( "\"%28x-3%2F2%29%5E2=7%2F4\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "\"x-3%2F2=0%2B-sqrt%287%2F4%29\" Take the square root of both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"x-3%2F2=sqrt%287%2F4%29\" or \"x-3%2F2=-sqrt%287%2F4%29\" Break up the \"plus/minus\" to form two equations.\r
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\n" ); document.write( "\n" ); document.write( "\"x-3%2F2=sqrt%287%29%2F2\" or \"x-3%2F2=-sqrt%287%29%2F2\" Simplify the square root.\r
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\n" ); document.write( "\n" ); document.write( "\"x=3%2F2%2Bsqrt%287%29%2F2\" or \"x=3%2F2-sqrt%287%29%2F2\" Add \"3%2F2\" to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"x=%283%2Bsqrt%287%29%29%2F%282%29\" or \"x=%283-sqrt%287%29%29%2F%282%29\" Combine the fractions.\r
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\n" ); document.write( "\n" ); document.write( "Answer:\r
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\n" ); document.write( "\n" ); document.write( "So the solutions are \"x=%283%2Bsqrt%287%29%29%2F%282%29\" or \"x=%283-sqrt%287%29%29%2F%282%29\".\r
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\n" ); document.write( "\n" ); document.write( "\"-x%5E2-8x%2B5\" Start with the given expression.\r
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\n" ); document.write( "\n" ); document.write( "\"-%28x%5E2%2B8x-5%29\" Factor out the \"x%5E2\" coefficient \"-1\". This step is very important: the \"x%5E2\" coefficient must be equal to 1.\r
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\n" ); document.write( "\n" ); document.write( "Take half of the \"x\" coefficient \"8\" to get \"4\". In other words, \"%281%2F2%29%288%29=4\".\r
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\n" ); document.write( "\n" ); document.write( "Now square \"4\" to get \"16\". In other words, \"%284%29%5E2=%284%29%284%29=16\"\r
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\n" ); document.write( "\n" ); document.write( "\"-%28x%5E2%2B8x%2Bhighlight%2816-16%29-5%29\" Now add and subtract \"16\" inside the parenthesis. Make sure to place this after the \"x\" term. Notice how \"16-16=0\". So the expression is not changed.\r
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\n" ); document.write( "\n" ); document.write( "\"-%28%28x%5E2%2B8x%2B16%29-16-5%29\" Group the first three terms.\r
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\n" ); document.write( "\n" ); document.write( "\"-%28%28x%2B4%29%5E2-16-5%29\" Factor \"x%5E2%2B8x%2B16\" to get \"%28x%2B4%29%5E2\".\r
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\n" ); document.write( "\n" ); document.write( "\"-%28%28x%2B4%29%5E2-21%29\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"-%28x%2B4%29%5E2%2B21\" Distribute.\r
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\n" ); document.write( "\n" ); document.write( "So after completing the square, \"-x%5E2-8x%2B5\" transforms to \"-%28x%2B4%29%5E2%2B21\". So \"-x%5E2-8x%2B5=-%28x%2B4%29%5E2%2B21\".\r
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\n" ); document.write( "\n" ); document.write( "So \"-x%5E2-8x%2B5=0\" is equivalent to \"-%28x%2B4%29%5E2%2B21=0\".\r
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\n" ); document.write( "\n" ); document.write( "Now let's solve \"-%28x%2B4%29%5E2%2B21=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"-%28x%2B4%29%5E2%2B21=0\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "\"-%28x%2B4%29%5E2=0-21\"Subtract \"21\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"-%28x%2B4%29%5E2=-21\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B4%29%5E2=%28-21%29%2F%28-1%29\" Divide both sides by \"-1\".\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B4%29%5E2=21\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B4=0%2B-sqrt%2821%29\" Take the square root of both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B4=sqrt%2821%29\" or \"x%2B4=-sqrt%2821%29\" Break up the \"plus/minus\" to form two equations.\r
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\n" ); document.write( "\n" ); document.write( "\"x=-4%2Bsqrt%2821%29\" or \"x=-4-sqrt%2821%29\" Subtract \"4\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "So the solutions are \"x=-4%2Bsqrt%2821%29\" or \"x=-4-sqrt%2821%29\".
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