x - 3 = - 5 is the way you write your given. Now all you have to do is add 3 to both sides.
x - 3 + 3 = - 5 + 3
x = - 2 Think of this as money. You are 5 dollars in debt. You find three dollars on the curb. You now a mere two dollars in debt.
Now you put - 2 in 3x - 9
3(-2) - 9
- 6 - 9
- 15.
The answer is 3.
