The perimeter is 46 meters and its length is 2 meters more than twice its width. What is the length?

In this problem, the length is compared to the width of the rectangle. So let's assign a variable that represents the width of the rectangle.  
Let the width be w.
width = w
Since the length is 2 meters more than twice its width, the expression that represent it is:
l e n g t h = 2w + 2
Then, plug-in the length and width to the formula of perimeter of rectangle.
P = 2*l e n g th + 2*width
P=2(2w+2)+2*w
Plug-in too the given perimeter of the rectangle.
46=2(2w+2)+2*w
Then, solve for w.
46=4w+4+2w
46=6w+4
42=6w
7=w
So, the width of the rectangle is 7 meters.  
Then, plug-in the value of w to the expression that represents the length.
l e n g t h = 2w + 2
l e n g t h = 2(7) + 2
l e n g t h = 14 + 2
l e n g t h = 16
 
Therefore, the length of the rectangle is 16 meters.