We have to use the Distributive Property in this equation.
By the Distributive Property,

becomes

Now we need to isolate x. Remember PEMDAS?


Simplify the right side.

Do you need to show your work ?
The 3 in 24,345 has a value of 300. A number 10 times that would have a value of 300*10 or 3,000. The 3 in choice C has a value of 3,000 so C is the right answer.
It would be obtuse.
Hope this helps :)