What is the condition that a is greater than or equal to minus 16 and less than or equal to 0

What is the condition that a is greater than or equal to minus 16 and less than or equal to 0

There exists x squared plus ax minus 4A less than 0
The negation of this proposition is: for any x ∈ R, the proposition that the square of x plus ax minus 4A > = 0 is true
Then the discriminant = a ^ 2 + 16A