Simplify 5a - 8c + b + 3c - 9a + 6b.
To simplify the expression 5a - 8c + b + 3c - 9a + 6b, we can combine like terms.
First, let's combine the a terms: 5a - 9a = -4a.
Next, let's combine the c terms: -8c + 3c = -5c.
Lastly, let's combine the b terms: b + 6b = 7b.
Putting it all together, we have: -4a - 5c + 7b.
Therefore, the simplified expression is -4a - 5c + 7b.