(a) \( x y+5 x y \)

Did you know that factoring expressions like \( x y + 5 x y \) can be traced back to ancient civilizations, like the Babylonians? They developed algebraic methods thousands of years ago! By recognizing common factors, you make math more efficient and unlock deeper structures within equations. In real-world applications, factoring is essential, especially in areas like engineering and physics. For example, when designing a bridge, engineers might use similar algebraic techniques to simplify load calculations, ensuring safety and efficiency! So, whether you’re constructing a building or solving a puzzle, factoring plays a crucial role!