Answer:
a + b
Step-by-step explanation:
Combine like terms: 5a - 2a - 2a = 1a; which can be written as simply "a"
continue with b: 5b + 2b - 6b = 1b: which can be written simply "b"
These terms are both positive so you can add to get your final simplified version: a + b
Hope this helps (: