Question 19138
STEP 1: you must add 3 on both sides of the equation (because the 3 has a negative in front of it, and you always do the opposite of what it tells you to do) 

STEP 2: you must cancel out both threes, by crossing them out (because that will give you zero and you do not want that as your answer, cause x is going to be greater than that, also I am not able to do so on here)

STEP 3: you must add the 3 to the 9

STEP 4: you should get 12 as your answer and now you must rewrite the equation again

STEP 5: Next you must subtract the 2 from the 12 (because 2 is a positive number and you always do the opposite of what the sign is in front of that number)you must cancel out both twos, by crossing them out (because that will give you zero and you do not want that as your answer, cause x is going to be greater than that, also I am not able to do so on here)

STEP 6: Now you will have now solved from x your answer should be x=10
  
PROBLEM BEING SOLVED:
2x-3y=9 
  +3=+3
---------
   2x=12
  -2  -2 
---------
    x=10

(As long as you were just doing basic Algebra, than all you really need to do was to solve for x. Also, I hope all my steps helped to simplify any confusion you might of had before I solved for this problem for you.)