It is known that the definition domain of quadratic function y = A & # 178; - 2a-1 is (- ∞, - 1) ∪ (3, + ∞) to find the minimum value of Y

It is known that the definition domain of quadratic function y = A & # 178; - 2a-1 is (- ∞, - 1) ∪ (3, + ∞) to find the minimum value of Y

Y = A & # 178; - 2a-1 = (A-1) ^ 2-2 the domain is (- ∞, - 1) ∪ (3, + ∞)
Axis of symmetry, x = 1
(- ∞, - 1] on the left side of the axis of symmetry, the function is a decreasing function
When x = - 1, y has the minimum value = 1 + 2-1 = 2
[3, + ∞) on the right side of the axis of symmetry, the function is an increasing function
When x = 3, y has a minimum value of 9-6-1 = 2