There are 3 rectangles.
In the plane, each rectangle has 2x + 7 horizontal side.
The fence covers 3 horizontal sides => 3 (2x + 7)
In the plane, the vertical sideis x. And the fence covers 4 vertical sides => 4x
Then the total amount of fecncin is: 3(2x+7) + 4x = 6x + 21 + 4x = 10x + 21
Answer: 10x + 21
