1. The problem is to understand the working of 1a, which seems to refer to a specific algebraic or mathematical expression or problem labeled as 1a. 2. Since the exact expression or problem 1a is not provided, please provide the full problem statement or expression for 1a so I can explain the working step-by-step. 3. Generally, to solve or explain a problem labeled 1a, we start by identifying the type of problem (e.g., equation solving, simplification, factorization). 4. Then, we apply relevant formulas or rules, such as distributive property, combining like terms, or solving equations. 5. Finally, we perform step-by-step calculations and simplify to reach the final answer. Please provide the exact problem 1a for a detailed explanation.