Answer
3 tablespoons of vinegar
Explanation:
First, this question direction's aren't really clear because the question is saying from my perspective:
Trevor used 2 things: Oil and Vinegar.
Then it says he used 3 times as much oil as vinegar
After it says he used 9 tablespoons of oil.
Lastly, the question asks for how many tablespoons of vinegar did he use?
9 Table Spoons of Oil is the Constant Variable or something that doesn't change in the problem
If he used 3 times as much oil then the equation would be
n x 3 = 9
n is representing the vinegar, 3 is representing the "3 times", 9 is the amount of oil Trevor uses.
You would then do 9/3 (9 divided by 3 since we are doing opposite operations to solve for n) which is equal to 3
In conclusion,
We needed to find the number of tablespoons of vinegar that Trevor used in his salad dressing, we know that 9 tablespoons is representing his oil, we wanted to find a number that is 3 times the tablespoons of vinegar but equalling to 9 since the oil is 3 times the vinegar. So the equation is n x 3 =9
Therefore, n=3 tablespoons of vinegar