Is this a linear equation

Which value of c would make he following expression completely factored? 8x+cy

David must install fencing around a lot that is shaped like a right angle.the side of lot that runs east-west is 200 ft long.the side of the lot runs north-south is 125 ft long.calculate how many feet of fencing he will need to surround the entire lot.

What is the difference between the predicted value and the actual value