document.write( "Question 1040891: If $s$ is a real number, then what is the smallest possible value of $2s^2 - 8s + 19$? \n" ); document.write( "
Algebra.Com's Answer #655834 by ikleyn(52781)\"\" \"About 
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\n" ); document.write( "If s is a real number, then what is the smallest possible value of 2s^2 - 8s + 19?
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document.write( "1.  Firmly memorize this:\r\n" );
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document.write( "    A quadratic function  y = \"ax%5E2+%2B+bx+%2B+c\"  has a minimum/maximum at  x = \"-b%2F2a\".     (1)\r\n" );
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document.write( "    To find this maximum/minimum value, substitute  x = \"-b%2F2a\"  into the quadratic function. \r\n" );
document.write( "    Then min/max, after calculations, is  \"-%28b%5E2-4ac%29%2F4a\".                              (2)\r\n" );
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document.write( "    Next,  if  a > 0  then the parabola is open up and the min/max is the minimum.\r\n" );
document.write( "           If  a < 0  then the parabola is open down and the min/max is the maximum.\r\n" );
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document.write( "2.  In your case,  the minimum is at s = \"-%28-8%29%2F%282%2A2%29\" = 2.\r\n" );
document.write( "    To calculate \"y%5Bmin%5D\", substitute s = 2 into the quadratic function.  It will produce the same value as (2), but the calculations are easier.\r\n" );
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document.write( "    \"y%5Bmin%5D\" = \"2%2A2%5E2+-8%2A2+%2B19\" = 8 - 16 + 19 = 11.\r\n" );
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\n" ); document.write( "\n" ); document.write( "See the lesson Who is who in quadratic equations in this site.\r
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document.write( "Next, memorize this:\r\n" );
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document.write( "     It doesn't matter which letter of the English alphabet is used in the parabola equation as a variable. \r\n" );
document.write( "     To find a min/max and a vertex coordinates, always use the formula (1). It works ALWAYS.\r\n" );
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document.write( "     After finding x, calculate the value of a min/max by substituting the found value  of \"x\" into the parabola equation.\r\n" );
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\n" ); document.write( "And the last notice.\r
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\n" ); document.write( "\n" ); document.write( "There is no need to use so many symbols \"$\" as you do.
\n" ); document.write( "We understand clearly your formulas without it.\r
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