## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$$2xy+2xz+x^2+y^2+2yz+z^2$$
We multiply the lengths of each side of the rectangle to find the total area of the figure: $$\left(x+y+z\right)\left(x+y+z\right) \\ 2xy+2xz+x^2+y^2+2yz+z^2$$