Question 819328
  <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
The standard form is {{{(x -h)^2 = 4p(y -k)}}}, where  the focus is (h,k + p)
f(x)= -(x+1)^2+4 
vertex-  V(-1,4)
line of symmetry-  {{{x = -1}}}
x intercept-   0 = -(x+1)^2 + 4,  x = -1  ± 2,  x is  -3,-1
y intercept- {{{ f(0) = -1 + 4 = 3}}}

   {{{drawing(300,300,   -6, 6, -6, 6, blue(line(-1,6,-1,-6))  , grid(1), 
circle(-1, 4,0.3),
circle(0, 3,0.3),
circle(1, 0,0.3),
circle(-3, 0,0.3),
graph( 300, 300, -6, 6, -6, 6,0,-(x+1)^2+4 ))}}}