√δ= a * a-4

When α> 2,

When a=2, -2, x ≠ 1 (corresponding respectively)

When -2 < a < 2, x∈R

2) The condition can be changed to f (2) ≤ 0.

∴4+2a+b-2=2a+b+2≤0

4-2a+b-2=-2a+b+2≤0

Linear programming a*a+b*b is used to represent the square of the distance from (a, b) to (0,0).

When A = 0 and b=-2, the minimum value of a*a+b*b is 4.