Answer:
<h2>y > 12</h2>
Step-by-step explanation:

y = -3(x<span> - 2)^2 + 1 </span>x<span>-coordinate of vertex: </span>x<span> = -b/(2a) = -12/-6 = 2 y-coordintae of vertex: y(2) = -12 + 24 - 11 = 1 </span>Vertex form: y = -3(x<span> - 2)^2 + 1 Check. Develop y to get back to standard form: y = -3(</span>x^2 - 4x + 4) + 1 = -3x<span>^2 + </span>12x<span> - </span>11<span>. </span>
This is impossible to answer without knowing what the sets A and B contain (and what ξ even refers to - universal set?).
However, we have
(A U B)' = A' ∩ B'
so that
(A ∩ B) U (A U B)' = (A ∩ B) U (A' ∩ B') = (A U A') ∩ (B U B')
If ξ is indeed the universal set, then both A U A' = ξ and B U B' = ξ, so we end up with ξ ∩ ξ = ξ.