Answer
See the graph
Work Step by Step
$f(x)=-2x^2+8x+9$
Find the axis of symmetry and the coordinates of the vertex.
$x=\frac{-b}{2a}=\frac{-8}{2.(-2)}=2$
The axis of symmetry is $x=2$. So the x-coordinate of the vertex is $2$
Substitute 1 for x to find the y-coordinate of the vertex.
$y=-2(2)^2+8(2)+9$
$=17$
The vertex is $(2,17)$
Find two other points for the graph.
$(0,9)$
$(1,15)$
Graph the vertex and the points we found.
