Tricky question. However, the key is to realize that ALWAYS when you have an equation with a number on the LHS you must do one thing immediately = factorization

Break down 546. The question has to deal with factors

Now, x and y the stem says might be >1 or 1

If the y in 7y is 1 we do have 7

So 6x * (7*1)=546

6x=78

x=13

x-y=13-1=12

the answer is C

PLEASE when you post a QCQ question the question itself must go under the right subforum: in this case QCQ and NOt quant general

Moreover, add the 4 answer options and format it via the tag quantity.

here is how to do it in one second https://gre.myprepclub.com/forum/how-to-po ... 12752.html

Thank you