Answer:
2.5
Explanation:
When a variable is next to a number (coefficient) it means you need to multiply. In this equation 6x are next to eachother.
Because we don't know what x is, we have to work backwards.
The opposite of multiplying is dividing, so here we can do...
15/6 and that equals 2.5
To check you replace x with 2.5 like so,
6(2.5)= 15 and it is true!
Hope this helps and have a great day!