The expression "a(b - c)" represents a mathematical operation involving multiplication and subtraction. In this expression, a is a coefficient that multiplies the result of the subtraction of c from b. This means you first calculate the difference between b and c, and then multiply that difference by a. For example, if a is 2, b is 5, and c is 3, you would first subtract 3 from 5, resulting in 2. Then, you multiply that result by 2, giving you a final answer of 4. This expression is commonly used in algebra to simplify calculations.