Question 609613
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Hi
Using the vertex form of a parabola, {{{y=a(x-h)^2 +k}}} where(h,k) is the vertex
1.vertex (0,-1) and (1,1) (-1,1) 
  y = ax^2 - 1
  1 = a· 1 - 1
  2 = a   and y = 2x^2 -1
2.vertex (2,4) and (1,1) (3,1) 
  y = a(x-2)^2 +4
  1 = a(3-2)^2 + 4
 -3 = a  and   y = -3(x-2)^2 +4
3.vertex is (-3,-3) and (2,4) (-8,4) 
  y = a(x+3)^2 -3
  4 = a(2 +3)^2 - 3
  7/25 = a  and  y = 7/25(x+3)^2 -3