Your equation [tex]f(x)=2x^2+4x+9[/tex] is in the form [tex]y=ax^2+bx+c[/tex] The vertex only relies on "a" and "b" though, so that +9 doesn't really matter in this case. The vertex of a parabola is located where [tex]x=\frac{-b}{2a}=\frac{-4}{2(2)}=-1[/tex] So your x-coordinate is -1. You need to find f(-1) to find your y-coordinate, and then you list it in the form (-1, y).
