Solve by completing the square

Imade a fort for my pet gorilla by connecting two boxes. the first box is 555 meters long, 999 meters wide, and 999 meters high. the second box is 333 meters long, 888 meters wide, and 222 meters high.how many cubic meters of space does my gorilla have to play in her fort?

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

Which is the completely factored from of xy^3-x^3y