Hello,

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 :

(16+2x)(20+2x)=464