document.write( "Question 287926: Express the function \"+f%28x%29=2x%5E2+-8x%2B3+\" in the form \"+f%28x%29=a%28x-h%29%5E2+%2Bk+\" by completing the square \n" ); document.write( "
Algebra.Com's Answer #208733 by jim_thompson5910(35256)\"\" \"About 
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\n" ); document.write( "\"2x%5E2-8x%2B3\" Start with the given expression.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%5E2-4x%2B3%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 \"-4\" to get \"-2\". In other words, \"%281%2F2%29%28-4%29=-2\".\r
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\n" ); document.write( "\n" ); document.write( "Now square \"-2\" to get \"4\". In other words, \"%28-2%29%5E2=%28-2%29%28-2%29=4\"\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x%5E2-4x%2Bhighlight%284-4%29%2B3%2F2%29\" Now add and subtract \"4\" inside the parenthesis. Make sure to place this after the \"x\" term. Notice how \"4-4=0\". So the expression is not changed.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x%5E2-4x%2B4%29-4%2B3%2F2%29\" Group the first three terms.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x-2%29%5E2-4%2B3%2F2%29\" Factor \"x%5E2-4x%2B4\" to get \"%28x-2%29%5E2\".\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x-2%29%5E2-5%2F2%29\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-2%29%5E2%2B2%28-5%2F2%29\" Distribute.\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-2%29%5E2-5\" Multiply.\r
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\n" ); document.write( "\n" ); document.write( "So after completing the square, \"2x%5E2-8x%2B3\" transforms to \"2%28x-2%29%5E2-5\". So \"2x%5E2-8x%2B3=2%28x-2%29%5E2-5\".\r
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\n" ); document.write( "\n" ); document.write( "So \"f%28x%29=2x%5E2-8x%2B3\" is equivalent to \"f%28x%29=2%28x-2%29%5E2-5\".\r
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\n" ); document.write( "\n" ); document.write( "So the equation \"f%28x%29=2%28x-2%29%5E2-5\" is now in vertex form \"f%28x%29=a%28x-h%29%5E2%2Bk\" where \"a=2\", \"h=2\", and \"k=-5\"
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