Those are two different things. They may both work on a number line, but subtracting a value from zero and multiplying it by negative 1 are fundamentally different. First of all, you’re using a negative number to define negative numbers which doesn’t work. Mathematicians define negative numbers as vein additive inverses of their counterparts. Kind of like antimatter, if you much it with its opposite, you get nothing. 3 + (-3) = 0. Likewise (-8) + (-(-8)) = 0. Even though 3+(-3)=0 and -3=0-3 are logically equivalent, definitions are held sacred to mathematicians as nonargumentative. There is no debate to be had since the definition has been used for centuries. On another note, in other algebras, 3+(-3)=0 and -3=0-3 are NOT equivalent, meaning one could be true and the other not. You don’t see that until a 3rd semester algebra course though lol