How do you know when you are finished gathering like terms?

You have to look at the equation to see if there are any other terms with the same variables.

Step-by-step explanation:

For example, take the equation

3x+7y - 16=-9+17x+y

First, you can combine the 3x and the 17x to equal 20x. Then you can combine the 7y and the 17y to get 24y. Then you can combine the - 16 and - 9 to get - 25. That gives us the equation 20x+24y-25. None of the other equations have a similar variable, so all of the like terms have been combined, and the equation is in its most simplified form.

There will be no more duplicates of the same term