The area of a rectangle is given by the product of its length and width. In this case, the dimensions of the rectangle are given as `-x + y + 2` and `x - 4`. Therefore, the area of the rectangle can be written as the product of these dimensions:

This product can be expanded to give the area as the sum of its parts:

Simplifying this gives:

So, the area of the rectangle can be written as either the product of its dimensions `(-x + y + 2)(x - 4)` or as the sum of its parts `-x^2 + (4 + y)x - 4y - 8`. Both expressions represent the same quantity, but in different forms.