In which expression should the exponents be multiplied

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.

Shortest side: xside two: x+26side three: 2xwork: x+x+26+2x=1304x+26=130 -26 -264x=104(4x=104)/4x=26check: 26+26+26+52=130shortest side length is 26 feet