The first step for solving this equation is to multiply both sides of the equation by 5.
9 - x = 15
Now move the constant to the right side of the equation and change its sign.
-x = 15 - 9
Subtract the numbers on the right side
-x = 6
Lastly,, change the signs on both sides of the equation to get your final answer.
x = -6
This means that the correct answer to your question is x = -6.
Let me know if you have any further questions
:)