Answer: 18a + 9
Step-by-step explanation: So let's simplify this problem using the distributive property.
The first thing we want to do is distribute or multiply this 9 times each of the terms inside the set of parentheses.
So we get 9 times 2a + 9 times 1.
So we have 9 (2a) + 9 (1) and this simplifies to 18a + 9.