Answer:
6
Step-by-step explanation:
The reason you would do 6 is because you need to isolate the variable term.
This means you need the variable and its coefficient alone. so if you subtract 6 from each side of the equation you can achieve that goal. So the equation would then read -2x= -9 (because you combine the like terms of -6 and the -3 that was already there)
If you need to complete the rest of the equation you would divide both sides by -2 to further isolate x. This means x= 9/2 (since they are both negative they cancel each other out turning it positive) and the simplified answer would be 4 1/2
Hope this helps <3