To find the difference (3c - d)² you should recognize that it is the square of a difference of two terms.
The square of the difference of two terms is a special case that you should remember: it is equal to the square of the first, minus twice the product of the first and second, plus the square of the second:
It is important when converting from square feet to square inches to remember to multiply twice. 166.47 times 12 times 12. Therefore the solution is 23971.68 square inches.
