Afarmer wants to build a fence along a river. he has 900 feet of fencing and wants to enclose a rectangular pen on three sides (with the river providing the fourth side). if x is the length of the side perpendicular to the river, determine the area a of the pen as a function of x.

The first thing we must do is define variables.

We have then:

x: the length of the side perpendicular to the river

y: the length of the side parallel to the river

The area of the rectangle is given by:

On the other hand, the perimeter of the rectangle is:

From here, we clear the value of y:

Then, rewriting the area we have:

the area of the pen as a function of x is:

the answer will be

answer: i'm great at algebra

~coco

step-by-step explanation: