To find the area of a square, you multiply the length of one side by itself. In this case, each side of the square is 5 units. Therefore, the expression that can be used to represent the area of the square is:
\(5 \times 5\) or \(5^2\)
This simplifies to \(25\). Hence, the correct answer is:
\(x^2 - 10x + 25\)
This expression represents the area of the square where each side is 5 units.