Question 463612
Other tutor did x-2, not x-3.


The surface area of a rectangular prism is SA = 2LW + 2WH + 2LH, but in the case of a cube, it can be reduced to 6s^2, where s is the side length. Here, s = x-3, so


SA = 6(x-3)^2 = 6(x^2 - 6x + 9) = 6x^2 - 36x + 54