# How do you write the expression for the area given the length (x+6) and width (x-3)?

Nov 23, 2016

For a rectangle the expression would be: $A = \left(x + 6\right) \cdot \left(x - 3\right)$ or $A = {x}^{2} - 3 x - 18$

#### Explanation:

The formula for area (assuming this is a rectangle) is:

$A = l \cdot w$ where $A$ is the area of the rectangle, $l$ is the length of the rectangle and $w$ is the width of the rectangle.

In this problem we are provided the length and width which we can substitute for the $l$ and $w$ is the formula to give:

$A = \left(x + 6\right) \cdot \left(x - 3\right)$

We can expand this to the form of a quadratic equation by cross multiplying to give:

$A = {x}^{2} + 6 x - 3 x - 18$

$A = {x}^{2} - 3 x - 18$