document.write( "Question 549192: write the quadratic function in vertex form:
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Algebra.Com's Answer #358314 by jim_thompson5910(35256)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "\"2x%5E2%2B11x%2B8\" Start with the given expression.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%5E2%2B%2811%2F2%29x%2B4%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 \"11%2F2\" to get \"11%2F4\". In other words, \"%281%2F2%29%2811%2F2%29=11%2F4\".\r
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\n" ); document.write( "\n" ); document.write( "Now square \"11%2F4\" to get \"121%2F16\". In other words, \"%2811%2F4%29%5E2=%2811%2F4%29%2811%2F4%29=121%2F16\"\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%5E2%2B%2811%2F2%29x%2Bhighlight%28121%2F16-121%2F16%29%2B4%29\" Now add and subtract \"121%2F16\" inside the parenthesis. Make sure to place this after the \"x\" term. Notice how \"121%2F16-121%2F16=0\". So the expression is not changed.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x%5E2%2B%2811%2F2%29x%2B121%2F16%29-121%2F16%2B4%29\" Group the first three terms.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x%2B11%2F4%29%5E2-121%2F16%2B4%29\" Factor \"x%5E2%2B%2811%2F2%29x%2B121%2F16\" to get \"%28x%2B11%2F4%29%5E2\".\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x%2B11%2F4%29%5E2-57%2F16%29\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%2B11%2F4%29%5E2%2B2%28-57%2F16%29\" Distribute.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%2B11%2F4%29%5E2-57%2F8\" Multiply.\r
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\n" ); document.write( "\n" ); document.write( "So after completing the square, \"2x%5E2%2B11x%2B8\" transforms to \"2%28x%2B11%2F4%29%5E2-57%2F8\". So \"2x%5E2%2B11x%2B8=2%28x%2B11%2F4%29%5E2-57%2F8\".\r
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\n" ); document.write( "\n" ); document.write( "So \"y=2x%5E2%2B11x%2B8\" is equivalent to \"y=2%28x%2B11%2F4%29%5E2-57%2F8\" which is the answer in vertex form.\r
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