Area of a square = Side × Side
Side = 7x-3
Area of the square = (7x-3) × (7x-3)
= 7x(7x-3) -3(7x-3)
= 49x^2 -21x -21x +9
=49x^2 -42x +9
Answer:
C. 468mm²
Step-by-step explanation:
The formula for the surface area of rectangular prism is:

Let's break down our variables.
L = 12mm
W = 6mm
H = 7mm + 2mm = 9mm
Now we substitute our values in the formula: