Answer
Please see the graph.
Work Step by Step
The graph was made using graphing software.
$f(x)=-\frac{4}{3}x^2-8x+8$
vertex
$x= -b/2a$
$x= -(-8)/2*-(4/3)$
$x = 8/-8/3$
$x = -3$
$f(-3)=-\frac{4}{3}(-3)^2-8*(-3)+8$
$f(-3)=-4/3 *9+24+8$
$f(-3) = -12 + 24+8$
$f(-3) = 20$
Two other points on the curve
$f(0) = -\frac{4}{3}(0)^2-8*(0)+8$
$f(0) = -4/3 *0-0+8$
$f(0) = 0+0+8 = 8$
$(0,8)$
Since $(0,8)$ is three units from the axis of symmetry, we also know $(-6,8)$ is on the graph.
