Question 636757
  <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi,
Note: the vertex form of a Parabola opening up(a>0) or down(a<0), {{{y=a(x-h)^2 +k}}} 
where(h,k) is the vertex  and  x = h  is the Line of Symmetry
f(x)= -2x^2-2x ={{{ -2(x+1/2)^2 + 1/2}}}     Note: {{{2/(2*2) = 1/2}}} & {{{(-2)(-1/4) = 1/2}}}
V(-1/2,1/2),  Parabola opens Downward, line of symmetry is x = -.5
{{{drawing(300,300,   -6, 6, -6, 6,  blue(line(-.5,6,-.5,-6))  , grid(1),
circle(-.5, 5,0.2),
graph( 300, 300, -6, 6, -6, 6,0,-2x^2-2x ))}}}