All squares are equal sides.Let X be the side of a square.Area of square,A = x^2
Here a tile is a square of side length 'x'. The following polynomial represents,
(x - 4) represents "the width of the new tile" (because 4 inches cut from the tile)
4x represents "the area removed from the tile" (since one side of removed tile is 'x' and other is 4 inches.)
x2 represents "area of original tile" of side equal to 'x'
x represents "the length of the new tile" (since length of new tile is not reduced. Length =x and breadth is x-4