document.write( "Question 264629: Complete the square,simplify. Express any complex numbers using i notation\r
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\n" ); document.write( "\n" ); document.write( "I am stuck because I can not figure out which 2 numbers multiply to 9 and add to 5.If I use (2x+3)(x+1) I can get 5x but no 9. Please help! This is where I always get stuck while factoring.
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Algebra.Com's Answer #194788 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
It turns out that you can't factor \"2x%5E2%2B5x-9\" over the rationals. So let's follow the instructions and complete the square.\r
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\n" ); document.write( "\n" ); document.write( "\"2x%5E2%2B5x-9\" Start with the given expression.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%5E2%2B%285%2F2%29x-9%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 \"5%2F2\" to get \"5%2F4\". In other words, \"%281%2F2%29%285%2F2%29=5%2F4\".\r
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\n" ); document.write( "\n" ); document.write( "Now square \"5%2F4\" to get \"25%2F16\". In other words, \"%285%2F4%29%5E2=%285%2F4%29%285%2F4%29=25%2F16\"\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%5E2%2B%285%2F2%29x%2Bhighlight%2825%2F16-25%2F16%29-9%2F2%29\" Now add and subtract \"25%2F16\" inside the parenthesis. Make sure to place this after the \"x\" term. Notice how \"25%2F16-25%2F16=0\". So the expression is not changed.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x%5E2%2B%285%2F2%29x%2B25%2F16%29-25%2F16-9%2F2%29\" Group the first three terms.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x%2B5%2F4%29%5E2-25%2F16-9%2F2%29\" Factor \"x%5E2%2B%285%2F2%29x%2B25%2F16\" to get \"%28x%2B5%2F4%29%5E2\".\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x%2B5%2F4%29%5E2-97%2F16%29\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%2B5%2F4%29%5E2%2B2%28-97%2F16%29\" Distribute.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%2B5%2F4%29%5E2-97%2F8\" Multiply.\r
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\n" ); document.write( "\n" ); document.write( "So after completing the square, \"2x%5E2%2B5x-9\" transforms to \"2%28x%2B5%2F4%29%5E2-97%2F8\". So \"2x%5E2%2B5x-9=2%28x%2B5%2F4%29%5E2-97%2F8\".\r
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\n" ); document.write( "\n" ); document.write( "So \"2x%5E2%2B5x-9=0\" is equivalent to \"2%28x%2B5%2F4%29%5E2-97%2F8=0\".\r
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\n" ); document.write( "\n" ); document.write( "Now let's solve \"2%28x%2B5%2F4%29%5E2-97%2F8=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%2B5%2F4%29%5E2-97%2F8=0\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%2B5%2F4%29%5E2=0%2B97%2F8\"Add \"97%2F8\" to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%2B5%2F4%29%5E2=97%2F8\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B5%2F4%29%5E2=%2897%2F8%29%2F%282%29\" Divide both sides by \"2\".\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B5%2F4%29%5E2=97%2F16\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B5%2F4=%22%22%2B-sqrt%2897%2F16%29\" Take the square root of both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B5%2F4=sqrt%2897%2F16%29\" or \"x%2B5%2F4=-sqrt%2897%2F16%29\" Break up the \"plus/minus\" to form two equations.\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B5%2F4=sqrt%2897%29%2F4\" or \"x%2B5%2F4=-sqrt%2897%29%2F4\" Simplify the square root.\r
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\n" ); document.write( "\n" ); document.write( "\"x=-5%2F4%2Bsqrt%2897%29%2F4\" or \"x=-5%2F4-sqrt%2897%29%2F4\" Subtract \"5%2F4\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"x=%28-5%2Bsqrt%2897%29%29%2F%284%29\" or \"x=%28-5-sqrt%2897%29%29%2F%284%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=%28-5%2Bsqrt%2897%29%29%2F%284%29\" or \"x=%28-5-sqrt%2897%29%29%2F%284%29\".
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