## Precalculus (6th Edition) Blitzer

$A=x(300-x)=300x-x^2$
Step 1. The perimeter of the rectangular fence can be expressed as $2(l+w)=600$, where $l,w$ are the length and width. Letting $x=w$, we have $l=300-x$ Step 2. The area can then be expressed as $A=lw=x(300-x)=300x-x^2$