Question

Is the equation `y=3` a direct variation, if so what is the constant of variation?

Answer 1

Actually, your equation represents something that doesn`t vary...

Explanation:

Well, this equation represents a CONSTANT. Basically, regardless to the real `x` value you may choose `y` will always be `3` and never change...
Graphically:
graph{0x+3 [-10, 10, -5, 5]}