
We divide first number from first parenthesis with first number from second parenthesis. Then the resulting number we multiply by all numbers in second parenthesis and substract from first parenthesis.

We repeat previous steps until we run out of numbers:


We are left with a number that has no x inside. This is remainder.
The final solution is sum of all these solutions and remainder:
Mean equals average
So 8 plus 10 equals 18
18 divided by 2 is 9
Mean is 9
I would say B, but do you have a graph to show? I'm confused.