Answer:
B
Step-by-step explanation:
The question you have to ask yourself is why did the 2 disappear on the left and why did the 10 decrease in the right.
Whatever you did, you didn't multiply to accomplish that, and you didn't add, both of which would have made things larger.
That leaves B and D. You have to consider D carefully. If you divide, that would make 2 smaller on the left, but it would never make the 2 disappear.
It would also reduce the 10, but the problem is that division would have to effect the x as well.
The answer is that B should be chosen. If you subtract 2 from both sides, the 2 on the left will disappear and you will reduce the 10 to 8 on the right.
I know my answer is a bit convoluted, but I hope it helps.