For the first one, let x be the width of the frame. As it is uniform, you don't have to care about its variation.
If you draw the thing, you may have a rectangle into another one (the frame).
You know the area of the big rectangle, which is 464.
The dimensions of this rectangle (the big one) is 16+2x and 20+2x (you add twice the width to the normal dimensions).
Hence the area of the rectangle is (16+2x)(20+2x) and is equal to 464.
So you have to solve for x in :