document.write( "Question 320535: The problem asks to find the vertex and graph the following quadratic function.
\n" ); document.write( "y=-x+6x
\n" ); document.write( " My professor says I need only turn in the coordinates. This is what I have tried... x=-b/2a = -6/2(-1) = -6/-2 =3 x=3\r
\n" ); document.write( "\n" ); document.write( "y=-2(3)^2+6(3)= -2(9) + 18 = -18 + 18=0 y=0 My book says the vertex is (3,9) so I am totally confused. I come up with (0,0) for the y intercept but I have no idea how that relates to me finding the coordinates for this graph. I have a very hard time grasping this concept. Thanks for your time.\r
\n" ); document.write( "\n" ); document.write( "Tracy Jones
\n" ); document.write( "

Algebra.Com's Answer #229549 by scott8148(6628)\"\" \"About 
You can put this solution on YOUR website!
y = -x^2 + 6x\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "you found the axis of symmetry OK (x = -b / 2a)\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "substituting back into the function ___ y = -(3^2) + 6(3) = -9 + 18 = 9\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "not sure where the x^2 coefficient of 2 comes from in your substitution?
\n" ); document.write( "
\n" );