If 3a and 2A + 5 are opposite to each other, then a is equal to?

If 3a and 2A + 5 are opposite to each other, then a is equal to?

That is - 3A = 2A + 5
5a=-5
a=-1

When x equals what, the sum of the squares of 2A + X and 6A equals 0?

2a+x+6a^2=0
x=-6a^2-2a

-X (x + 1) (x-1) + X (the square of X-2) (greater than or equal to 0)

-X (x + 1) (x-1) + X (the square of X-2) ≥ 0
-x(x^2-1)+x^3-2x≥0
-x≥0
x≤0

Given a = {the square of X / X - X-2 is less than or equal to 0} B = {X / 2a is less than X and less than a + 3} if a intersects B = an empty set, find the range of A

First of all, you have to consider two cases. If B is an empty set, the condition is 2A