Answer:
Commutative law of addition
Explanation:
a +[b+12] = [b+12] +a
The commutative law of addition states that when two variables are added the answer remains the same irrespective of the position of the variables but the variable must be equal .
This can be explained by numbers .
Suppose we have two numbers 4 and 7 then the law can written as
4+7= 7+4
11= 11
We see we get the same answer whether 4 is written before or after 7.
Similarly in the given equation we have two variables ,
one is a the other is [b+12] . So it does not matter whether a is written before or after [b+12] in addition.
Hence it satisfies the commutative law of addition
a +[b+12] = [b+12] +a
a+b+12= b+12 +a
a+b+12= a+b+12
After solving we will get the same answer on both sides.