[tex]f(x)=2x^2+4x+9 \\
a=2 \\ b=4[/tex]
The coordinates of the vertex of a parabola are (h,k) where:
[tex]h=\frac{-b}{2a}=\frac{-4}{2 \times 2}=\frac{-4}{4}=-1 \\ \\
k=f(h)=f(-1)=2 \times (-1)^2+4 \times (-1)+9=2 -4+9=7[/tex]
The coordinates of the vertex are (-1,7).
