1. The length, width, and height of a rectangular prism can be represented by the expressions (r + 3),

(x + 7) and (x - 1). Write an expression to represent the surface area of the prism.

6x² + 36x + 22

Step-by-step explanation:

2 faces (x + 3) by (x + 7), area of both these faces 2 (x+3) * (x + 7)

2 faces (x + 3) by (x - 1), area of both these faces 2 (x+3) * (x - 1)

2 faces (x - 1) by (x + 7), area of both these faces 2 (x-1) * (x + 7)

Whole surface area is

2 (x+3) * (x + 7) + 2 (x+3) * (x - 1) + 2 (x-1) * (x + 7) =

=2 (x² + 3x + 7x + 21) + 2 (x² + 3x - x - 3) + 2 (x² - x + 7x - 7) =

=2x² + 20x + 42 + 2x² + 4x - 6 + 2x² + 12x - 14 =

= 6x² + 36x + 22