document.write( "Question 170246: find the quadratic function whose vertex is (-1,5) and passing through the point (2,7) and graph the function.
\n" ); document.write( "need answer before 12/1/08 \n" ); document.write( "
Algebra.Com's Answer #125686 by nerdybill(7384)\"\" \"About 
You can put this solution on YOUR website!
Reviewing vertex formula:
\n" ); document.write( "http://www.mathwarehouse.com/geometry/parabola/standard-and-vertex-form.php
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\n" ); document.write( "Standard \"vertex form\":
\n" ); document.write( "y= a(x-h)^2+k
\n" ); document.write( "where
\n" ); document.write( "(h,k) is the vertex
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\n" ); document.write( "The problem gives you:
\n" ); document.write( "(h,k) = (-1,5)
\n" ); document.write( "(x,y) = (2,7)
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\n" ); document.write( "Plug the above into:
\n" ); document.write( "y= a(x-h)^2+k
\n" ); document.write( "7= a(2-(-1))^2+5
\n" ); document.write( "Solve for 'a':
\n" ); document.write( "7= a(2+1)^2+5
\n" ); document.write( "7= a(3)^2+5
\n" ); document.write( "7= 9a+5
\n" ); document.write( "2 = 9a
\n" ); document.write( "2/9 = a
\n" ); document.write( ".
\n" ); document.write( "Therefore:
\n" ); document.write( "y= a(x-h)^2+k
\n" ); document.write( "y= (2/9)(x-(-1))^2+5
\n" ); document.write( "y= (2/9)(x+1)^2+5
\n" ); document.write( "y= (2/9)(x^2+2x+1)+5
\n" ); document.write( "9y= 2(x^2+2x+1)+45
\n" ); document.write( "9y= 2x^2+4x+2+45
\n" ); document.write( "9y= 2x^2+4x+47
\n" ); document.write( "y = (2/9)x^2 + (4/9)x + (47/9)\r
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