Answer:
10x
Explanation:
The height on the left is the same as the height on the right:
(2x -y) +(y) = (2x)
2x = 2x . . . . . not particularly helpful
The width across the top is the same as the width across the bottom:
3x = (y) +(4x -2y)
y = x . . . . . . . . add y-3x to both sides
The perimeter is the sum of side lengths. Working clockwise from the top, that is ...
P = 3x +2x +(4x-2y) +y +y +(2x -y) = 11x -y = 10x
The perimeter is 10x. (or 10y, if you like)