PLEASE HELP WILL MARK AS BRAINLIEST THE QUESTION IS BELOW

Answer:
Step-by-step explanation:
First you have to split the shape into 2. I split the box so that the little one's length is Z and width is x. Find the area of both boxes:
Box 1:
Z x X = ZX
Box 2:
Y x (Z + X) = Y(Z + X)
So the overall area of the box is:
ZX + Y(Z + X)
I'm not quite sure how to explain this without pictures to show you but i hope this helps. Let me know if you have any questions