Which expressions are equivalent after simplifying? Check all that apply. (3.1a – 2.7b) + (1.5a – 4.9b) (2.3a + 0.2b) – 8b (–3.5b + a) – (4.1b – 3.6a) –0.4b + (8b + 4.6a) 4.6a – 7.6b