document.write( "Question 37236: Create the quadratic equation in the form ax squared + bx + c using the point
\n" ); document.write( "(-1,7) as one point and the point (10,-8) as the vertex. enter a,b,c values as common fractions in reduced form. \r
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\n" ); document.write( "\n" ); document.write( "i have several problems just like this to answer. i need to know how to come up with the equation. please help. cheryl mitchell clm031303@yahoo.com \n" ); document.write( "
Algebra.Com's Answer #22919 by AnlytcPhil(1806)\"\" \"About 
You can put this solution on YOUR website!
Create the quadratic equation in the form \r\n" );
document.write( "y = ax² + bx + c using the point (-1,7) as one\r\n" );
document.write( "point and the point (10,-8) as the vertex. \r\n" );
document.write( "Enter a,b,c values as common fractions in \r\n" );
document.write( "reduced form. \r\n" );
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document.write( "We start out with the standard form:\r\n" );
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document.write( "y = a(x - h)² + k where the vertex is \r\n" );
document.write( "(h, k) = (10, -8).  Substituting:\r\n" );
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document.write( "y = a(x - 10)² - 8\r\n" );
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document.write( "Now this must go through the point (-1, 7), \r\n" );
document.write( "so substitute -1 for x and 7 for y, and \r\n" );
document.write( "solve for a:\r\n" );
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document.write( "           7 = a(-1 - 10)² - 8\r\n" );
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document.write( "           7 = a(-11)² - 8\r\n" );
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document.write( "           7 = a(121) - 8\r\n" );
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document.write( "           15 = 121a\r\n" );
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document.write( "       15/121 = a\r\n" );
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document.write( "Now y = a(x - 10)² - 8 becomes\r\n" );
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document.write( "    y = 15/121(x - 10)² - 8\r\n" );
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document.write( "Clear of fractions temporarily by multiplying \r\n" );
document.write( "both sides by 121:\r\n" );
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document.write( "   121y = 15(x - 10)² - 968\r\n" );
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document.write( "   121y = 15(x² - 20x + 100) - 968\r\n" );
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document.write( "   121y = 15x² - 300x + 1500 - 968\r\n" );
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document.write( "   121y = 15x² - 300x + 532\r\n" );
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document.write( "Divide through by 121\r\n" );
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document.write( "      y = (15/121)x² - (300/121)x + 532/121\r\n" );
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document.write( "a = 15/121, b = -300/121, c = 532/121\r\n" );
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document.write( "Edwin\r\n" );
document.write( "AnlytcPhil@aol.com
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