Final answer:
To find the LCD of the rational expressions, factor the denominators and identify the common factors.
Step-by-step explanation:
In order to find the LCD (Least Common Denominator) of the rational expressions, we need to factor the denominators and identify the common factors. Let's start with the first expression, 7/(3x+18). The denominator can be factored as 3(x+6). Now let's look at the second expression, 9/(5x-35). The denominator can be factored as 5(x-7). The common factors are 3 and 5, so the LCD is 3 * 5 * (x+6) * (x-7), which can be simplified as 15(x+6)(x-7).