Given the complete set u = R, set a = {a | a ≥ 2, or a ≤ - 2}, B = {a | the equation AX ^ 2-x + 1 = 0 of X has real roots}, find a ∪ B, a ∪ (cub)

Given the complete set u = R, set a = {a | a ≥ 2, or a ≤ - 2}, B = {a | the equation AX ^ 2-x + 1 = 0 of X has real roots}, find a ∪ B, a ∪ (cub)

On the equation AX ^ 2-x + 1 = 0 of X has real roots
aX^2-X+1=0
b^2-4ac≥0
1-4a≥0
a≤1/4
U = R, a = {a | a ≥ 2, or a ≤ - 2}, B = {a | a ≤ 1 / 4}, Cub = {a | a > 1 / 4}
A∪B={a|a≤1/4}
A∪（CuB）={a|a>1/4}

U = R, set a = [x, X is less than 1, or X is greater than 2], set B = [x, X is less than - 3, or X is greater than or equal to 1], find the complement of a, the complement of B a intersects B, and B intersects a

The complement X of a is greater than or equal to 1 and less than or equal to 2
The complement X of B is greater than or equal to - 3 and less than 1
A cross B x less than - 3 or x greater than 2
B and a r

It is known that the set u = {X / X is greater than or equal to 2}, and the set a = {Y / 3 is less than or equal to y

The complement intersection of a = empty set