It is 400 dollars since 5 yards and 4 yards which are the dimensions of this room is multiplied together, it is 20 and each square yard is 20 dollars which concludes you to multiply 20 by 20 and gives us the answer 400.
Divide both sides by 1-y. Divide both sides by 1−y. Dividing by 1-y undoes the multiplication by 1-y. Dividing by 1− y undoes the multiplication by 1−y. Subtract xy from both sides. Subtract xy from both sides.
