How do you multiply #(2a + 3b)(6a + 9b)#?
Multiply each term of the first binomial by each term of the second binomial. In other words, multiply 2a by 6a, 2a by 9b, 3b by 6a, and 3b by 9b. Then add like terms.
Multiply each term in the first binomial by each term in the second.
Combine like terms.