The properties that can be used to show these expressions are equivalent are associative and distributive.
This property implies that rearranging the terms of a mathematical operation does not change its results.
This occurs in this case because by using 5x +x or 6x you are rearranging the terms but the result would be the same.
This property implies terms can be distributed in different ways without changing the result.
Learn more about distributive property in: https://brainly.com/question/13130806