we know that
the area of a square=b²
where
b is the side length of the square
in this problem
the length of one side of a square is represented by the function
S(x) = 3x – 2
so
Area of the square=[S(x)]²----> (3x-2)²----> 9x²-12x+4
the answer is the option
A. (S^2)(x) = 9x^2 – 12x + 4
