3-(1+x)+4x
Since it's just addition and subtraction, you can just remove the brackets (i.e., you do not need to worry about the order of operations since there is no multiplication or division).
So we have,
3-1+x+4x
Now, we just combine the like terms (the numbers and the term with x's in them)
3-1 gives 2 and x + 4x gives 5x (Think of it as one orange plus 4 oranges).
Hence we end up wiht 2 + 5x.