Which of the following is equivalent to 9^3/4

Well 9^3/4 is:
9*9*9=729
729/4=182.25 (182.3)

Subtracting is the opposite of adding

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.