You should understand that this is not a homework service nor is it a tutorial service. We help people who already have a basic grasp of the material.
You posted the question. Therefore, you should know what the symbols mean. Frankly, I do not know what means in this context. I guess it probably means the set complement.
That is why you have text material. The identity is still correct.
For every set it is the case that . It is true .