Answer:
Either 0, 12, or 9 (Possibly)
Explanation:
I'm assuming that you forgot to put the x next to 4.5 or 1.5 or that you forgot to put x next to both of them and that =3 means x=3
Case 1 (4.5x - 1.5x, x = 3):
You can simplify this expression because both of the units are the same (x). 4.5x - 1.5x = 3x. Next, you have to plug in 3, which would be 3 * 3 which is 9.
Case 2 (4.5x - 1.5, x = 3):
Plug in 3 and you would get 13.5 (4.5 * 3) - 1.5, which is equal to 12.
Case 3 (4.5 - 1.5x, x = 3):
Plug in 3 and you would get 4.5 - 4.5 (1.5 * 3), and since they are the same, it is equal to 0.
If none of these are the answer or you are asking something else, feel free to comment on this answer
-Hope this helped-