Answer:
It's the 3rd one: Commutative Property of Equality.
Step-by-step explanation:
Original: 3a + 6 = 2 - 5a + 7
But then on step one, the -5a was moved around. The -5a took the position of where the +7 was located and the +7 took the position of where the - 5a was located. (Basically, they switched)
Step one: 3a + 6 = 2 + 7 -5a
(I really hope this helps.)
