Let's solve the problem step by step.

We are given:

$[6(xy + 3) - 4xy] - 4(xy + 3)$

Step 1: Distribute the terms inside the brackets.

1. $6(xy + 3)$ becomes: $6xy + 18$

2. $-4(xy + 3)$ becomes: $-4xy - 12$

Now, rewrite the expression:

$(6xy + 18 - 4xy) - (4xy + 12)$

Step 2: Combine like terms.

• $6xy - 4xy = 2xy$
• $18 - 12 = 6$

Thus, the simplified expression is:

$2xy + 6$

Answer:

The correct choice is D. 2xy + 6.

Would you like any additional details or clarifications on this? Here are five related questions:

1. How do you combine like terms in algebraic expressions?
2. What is the distributive property, and how does it apply here?
3. How can we verify if our simplification is correct?
4. What are common mistakes to avoid when distributing and combining terms?
5. How would the answer change if the signs of terms were different?

Tip: Always double-check parentheses and distribution, as they can lead to errors in simplification!