Kind of hard to tell what’s a plus and minus sign so maybe some of these are incorrect.
The first one says x+2x+4y.
So the first thing you would do is combine like terms.
x and 2x are like terms.
Since x has no number you would have to put a 1 in place for it.
So you would have 1x+2x which would be 3x.
You would then put that together and have 3x+4y.