There are many ways you could solve this equation. We need to get k alone on one side, and a constant number alone on the other side. Since k is inside the parentheses on the left, we can use the distributive property to rewrite the equation without parentheses. Go for it. Distribute the 1/3 to 12k - 9. You can think of this as (12k - 9) is being multiplied by 1/3 .
1/3 (12k - 9) = 8k + 9
_____ = 8k + 9
