# Question #fb1f8

Jan 27, 2017

$A = l \left(l - 45\right)$

or

$A = {l}^{2} - 45 l$

#### Explanation:

Let's define the length of the soccer field as $l$.

The width of the soccer field can then be defined as $l - 45$

The formula for the area of a rectangle (a soccer field is assumed to be rectangular so it is valid to use this formula) is:

$A = l \times w$

Where:
$A$ is the area
$l$ is the length, which for this problem we have defined as $l$
$w$ is the length, which for this problem we have defined as $l - 45$

Substituting our definition gives:

$A = l \times \left(l - 45\right)$

$A = \left(l \times l\right) - \left(l \times 45\right)$

$A = {l}^{2} - 45 l$