Question

The rectangle below has an area of x^2 - 9 square meters and a width of x - 3 meters.

What expression represents the length of the rectangle?

Answer 1

x+3

Explanation:

Area of a rectangle is
`L\cdot W`.

We know the width, W, is
`x-3` and we know the area is
`x^2-9`.

Inputting this in our formula above we get:

`x^2-9=L(x-3)`

L is a an expression such that when you multiply it to
`(x-3)` gives you
`(x^2-9)`.

`x^2-9` is a difference of squares and can be factored using:

`a^2-b^2=(a-b)(a+b)`.

`x^2-9=(x-3)(x+3)`.

So L=x-3 and W=x+3.