How do I solve this math project problem? They don't give me a formula for the quadratic function, or explain the variables.

Question

The question is

"You've been given $500.00 for your fencing. So first we are going to make as big of a rectangular field as we can with the money that we have for the fencing to surround it. The cost of the premium fencing (only the best for your farm of course) is $11.41 per metre. So with that, and the following equations,

A=l*w

P=2l+2w

Where A is the area, P s the perimeter, l is the length, and w is the width of a rectangle, we can find the maximum area that we can have for this field. You should encounter a quadratic function, so using a graphing calculator, or an online graphing website will help you see what that looks like. You can then use previously learned methods to fid the maximum of this function"

They did not teach me how to do this please help

Answer 1

500/4 = 125

125/11.41= 10.9553 meters = length=width

120.0186 m^2 = max area for $500