Formula to find the surface area of the rectangular prism is:
2wl + 2lh + 2hw,
where w is width, l is the length, and h is height of the prism.
Given, the dimension x units ,2x units and x+8 units .
So, we can plug in w= x, l= 2x and h= x+8 in the above formula to get the expression for the surface area of the prism. Hence,
Surface area= 2wl + 2lh + 2hw
=2*x*2x+ 2*2x*(x+8)+2*(x+8)*x
= 4x²+4x(x+8)+2x(x+8) (By multiplying)
= 4x²+4x²+32x+2x²+16x (Multiplying by distribution)
=(4x²+4x²+2x²)+(32x+16x ) (Making the groups of like terms)
= 10x²+48x (Adding the like terms)
So, the expression 10x²+48x units² represents the surface area of the given prism.