Answer:
6a - 9
Step-by-step explanation:
First off, let's put all of the identical variables besides each other, to make this equation easier.
-5ab - (-5ab) + 6a - 8 - 1
Then, we simply solve.
-5ab + 5ab = 0
6a = 6a
-8 - 1 = -9
So you're left with 6a - 9 as your answer.
Hope that helps!