For the first one, Rafiki is correct. Multiply each side by 3 to get x by itself and because 3 isn't negative, the sign stays the same.
For the second one, Duey is right because to get rid of a number in a equation subtract or add (depending on whether the number is positive or negative) from both sides.
For the last one I don't think aby of them are right.
Hope this helps!
