Answer:

Step-by-step explanation:
Let's define some notation first:
L = represent the length for the rectangle
A = represent the area for the rectangle
W= represent the width for the rectangle
From the info given we know that P= 12m
And the perimeter for a rectangle is given by:

From this equation we can solve for W like this:


Now we can use the formula for the area of a rectangle given by:

And if we replace the expression founded for W, we got:


And that would be our final answr in terms of the length.