document.write( "Question 123071: Find numbers a and b so that x^2+4x+9=(x+a)^2+b \n" ); document.write( "
Algebra.Com's Answer #90333 by jim_thompson5910(35256)\"\" \"About 
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\n" ); document.write( "\"y=x%5E2%2B4+x%2B9\" Start with the given equation\r
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\n" ); document.write( "\n" ); document.write( "\"y-9=x%5E2%2B4+x\" Subtract \"9\" from both sides\r
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\n" ); document.write( "\n" ); document.write( "Take half of the x coefficient \"4\" to get \"2\" (ie \"%281%2F2%29%284%29=2\").\r
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\n" ); document.write( "\n" ); document.write( "Now square \"2\" to get \"4\" (ie \"%282%29%5E2=%282%29%282%29=4\")\r
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\n" ); document.write( "\n" ); document.write( "\"y-9=x%5E2%2B4x%2B4-4\" Now add and subtract this value inside the parenthesis. Doing both the addition and subtraction of \"4\" does not change the equation\r
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\n" ); document.write( "\n" ); document.write( "\"y-9=%28x%2B2%29%5E2-4\" Now factor \"x%5E2%2B4x%2B4\" to get \"%28x%2B2%29%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28x%2B2%29%5E2-4%2B9\" Now add \"9\" to both sides to isolate y\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28x%2B2%29%5E2%2B5\" Combine like terms\r
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\n" ); document.write( "\n" ); document.write( "So what we've done is complete the square and convert \"y=x%5E2%2B4+x%2B9\" into
\n" ); document.write( "\"y=%28x%2B2%29%5E2%2B5\"\r
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\n" ); document.write( "\n" ); document.write( "So this means that \"x%5E2%2B4x%2B9=%28x%2B2%29%5E2%2B5\" which in turn also means \"%28x%2B2%29%5E2%2B5=%28x%2Ba%29%5E2%2Bb\"\r
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\n" ); document.write( "\n" ); document.write( "Here we can see that \"a=2\" and \"b=5\"\r
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\n" ); document.write( "\n" ); document.write( "So our answers are: \"a=2\" and \"b=5\"
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