Essay. Show all work. A school designer wants to create a whiteboard with the optimal dimensions to enhance learning. it is determined that if one side of the whiteboard is x+y inches, the other side should be x^2+6xy-4y^2 inches. Write an algebraic expression for the area of such a whiteboard, simplify it, and include correct units with your solution.
A = (x+y)(x^2+6xy-4y^2),
A = x^3+6x^2y-4xy^2+x^2y+6xy^2-4y^3,
A = x^3 + 7x^2y + 2xy^2 - 4y^3 sq in.