Answer:The answer is A - symmetry.
None of the other options really have bearing in relation to the question.
Step-by-step explanation:
Answer:
Option A is correct.

Step-by-step explanation:
Simplify:
......[1]
Like terms are those terms who have same variable to the same power.
Combine like terms in [1] ,we have;
Simplify:

Therefore, the simplified form of
is, 
Answer:
-a-13
Step-by-step explanation:
-2 * (a+3)
-2a - 6 -7 + a
-2a+a = -a
-6-7= -13
-a - 13