tell me if the way I did it include commutative, associative, distributive or combined like terms in my problem

Explanation:
The commutative property said that:
a + b = b + a
The associative property said that:
a + b + c = (a + b) + c
So, in the first step, you apply commutative property when you reorganize the terms, and then, you apply associative property when you add the brackets
Finally, on the second step, you combined like terms because 6x, -x, and 2x are like terms.