Question

A rectangle has length that is 5 less than 2 times the width. Write an expression for the area of the rectangle.

Answer 1

We are given a relationship between the sides of a rectangle, that is, the length of one of its sides is 5 less two times its width, and we are asked to find an expression for the area. Let's remember that the area of a rectangle is equal to the product of the length of its side by its width. Let "w" be the length of the rectangle and "L" its lenght, then the area is given by the following formula:

$A=Lw$

We can use the relationship given in the problem, that is, its length being five less two times its width, that is:

$L=5-2w$

Replacing in the formula for the area we get:

$A=(5-2w)w$

Now we use the distributive law:

$A=5w-2w^2$