A piece of land is to be fenced and subdivided as shown so that each rectangle has the same dimensions. Express the total amount of fencing needed as an algebraic expression in x. Viewed from the above, a piece of land has a rectangular shape with a left vertical side of width x and a right vertical side of unknown width. Two vertical fences divide the land into three equally sized rectangles. The horizontal side of the leftmost rectangle has a length of 3x plus 7, and the length of the horizontal side of the other two rectangles is unknown.