Combining like terms:
This means to bring together terms that are of the same variable to the same degree in order to use on them, the addition or dubtraction operator.
For example, 2x and 3x are like terms because they both have the same variable (x) to the first degree. This means that tyou can use the addition or subtraction operator to act on them
Similarly, 2x² and 5x² are like terms because they both contain the second degree of x.
Commutative property:
The commutative property holds if the order of terms does not affect the result gotten when an operator (addition and mutiplication) act on them
a + b = b +a
ab = ba
You can see from the examples above, that the order of the variables does not affect the result
Associative property:
The associative property holds when the arrangement of the parenthesis does not affect the result.
a x (b x c) = (a x b) x c
a + (b + c) = (a + b) + c