Final answer:
To find the LCD, factor the terms and multiply the denominators. Then, add the rational expressions.
Step-by-step explanation:
To find the LCD (Least Common Denominator) of the expression (y - 3)(6y), we need to determine the factors that are common to both terms. In this case, y - 3 can be factored as y - 1 * 3, which means the LCD is (y - 1)(3)(6y). When multiplying rational expressions, we multiply the numerators together and multiply the denominators together. So, the sum of the rational expressions would be (A * (y - 1)(3)(6y) + B * (y - 1)(3)(6y)) / ((y - 1)(3)(6y)).