Question

The length of a side of a rectangle is 2 units less than a number, and the width is 4 units more than the length. Which of the following expressions represents the area of the rectangle, in square units?

Answer 1

Let's find the expressions for the length and width of the rectangle. The length (which we will call l) is 2 units less than some undefined number, thus we will use the variable x:
l = x - 2

The width is 4 more than this length:
w = l + 4 = (x - 2) + 4 = x + 2

Now, given that we have the length and width and are looking for the area, we need to multiply these expressions together.

One way to write this would simply be (x + 2)(x - 2). If we wanted to find a different way of writing the area, we could use FOIL to find all terms and get x^2 - 4.