document.write( "Question 1148201: How do i make a quadratic equation from vertex point (4,-3) and point (6,-1)? \n" ); document.write( "
Algebra.Com's Answer #769595 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "Start with the vertex form of the equation, as tutor @MathTherapy did:

\n" ); document.write( "\"y+=+a%28x-h%29%5E2%2Bk\"

\n" ); document.write( "With the vertex given as (4,-3), the equation in this form is

\n" ); document.write( "\"y+=+a%28x-4%29%5E2-3\"

\n" ); document.write( "Then here is an alternative method for determining the value of a to complete the equation.

\n" ); document.write( "(1) The point other than the vertex that is given is 2 units to the right of the vertex.
\n" ); document.write( "(2) If a were 1, so that the graph behaved like y=x^2, then the y value 2 to the right of the vertex would be 2^2=4 greater than the y value at the vertex.
\n" ); document.write( "(3) But the y value 2 to the right of the vertex is only 2 greater than the y value at the vertex.

\n" ); document.write( "Since the y value increased only half as much as it would have increased if a were 1, a must be 1/2.

\n" ); document.write( "So the equation is

\n" ); document.write( "\"y+=+%281%2F2%29%28x-4%29%5E2-3\"

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