I agree with Jack...to solve for the unknown, in this case X, you first have to isolate it from all the known values. The only thing I would add is that when subtracting or adding fractions, you first have to have the denominators be the same. Here they are (4/3 and 1/3) so you just subtract one from four, which leaves you with 3/3, which is the same as 1. Had the denominators not been the same, you would have first had to multiply one or both fractions by the appropriate value to create the same denominator. Ex: had the question been 4/3=x+1/5, you would first have to find a common multiple of 3 and 5 (which is 15) and multiply accordingly...4 times 5 and 3 times 5 to get 20/15 and 1 by 3 and 5 by 3 to get 3/15. Since the denominators are now the same, you can now subtract 3/15 from 20/15 which is 17/15 or 1 and 2/15, or 1.13333.