Simplify
x-3/3-x-2/5
The above means the following:
. . . . .$\displaystyle x\, -\, \frac{3}{3}\, -\, x\, -\, \frac{2}{5}$
If this is what you meant, then subtract the x's and then note that 3/3 = 1 = 5/5, and add the -5/5 and the -2/5.
If, on the other hand, you meant the following:
. . . . .$\displaystyle \frac{x\, -\, 3}{3}\, -\, \frac{x\, -\, 2}{5}$
...then you need to convert the two fractions to a common denominator:
. . . . .$\displaystyle \frac{5(x\, -\, 3)}{3\times 5}\, -\, \frac{3(x\, -\, 2)}{5\times 3}$
Multiply out, and then simplify across the top.