document.write( "Question 1146110: Write an equation for the parabola in standard form. Use a graphing utility to graph the equation and verify your result.
\n" ); document.write( "f(x) = \r
\n" ); document.write( "\n" ); document.write( "Point: (0,7)
\n" ); document.write( "Vertex:(-3,-2)
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Algebra.Com's Answer #767402 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "As in the response from the other tutor, a vertex at (-3,-2) means the equation is of the form

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

\n" ); document.write( "or

\n" ); document.write( "\"y%2B2+=+a%28x%2B3%29%5E2\"

\n" ); document.write( "or

\n" ); document.write( "\"y+=+a%28x%2B3%29%5E2-2\"

\n" ); document.write( "Then here is a different way to determine the value of the constant a to complete the equation.

\n" ); document.write( "Note that the constant a determines how steep the parabola is.

\n" ); document.write( "Then note that the given point on the parabola is 3 units to the right of the vertex and 9 units up from the vertex.

\n" ); document.write( "Then, since 9 is 3^2, you know the constant a is 1, so the equation is

\n" ); document.write( "\"y+=+%28x%2B3%29%5E2-2\"
\n" ); document.write( "\"y+=+%28x%5E2%2B6x%2B9%29-2\"
\n" ); document.write( "\"y+=+x%5E2%2B6x%2B7\"

\n" ); document.write( "Let's look again at this method for determining the value of the constant a in the equation.

\n" ); document.write( "Suppose the given point were (1,6).

\n" ); document.write( "That point is 4 to the right of the vertex and 8 units up from the vertex.

\n" ); document.write( "Since 4^2 is 16 and the point is only 8 units up from the vertex, the value of the constant a is 8/16 = 1/2.

\n" ); document.write( "And one more example, to help you try to see how this method works.

\n" ); document.write( "This time the given point is (-1,10). That point is 2 to the right and 12 up from the vertex. Since 2^2 is 4, the value of the constant a is 12/4 = 3.
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