3a-(2a-6)-(3a-2)-(a-3)

Let's simplify the expression step by step:

Given: \( 3a - (2a - 6) - (3a - 2) - (a - 3) \)

1. Distribute the negative signs: \[ 3a - 2a + 6 - 3a + 2 - a + 3 \]

2. Combine like terms:

   • First, combine the \( a \) terms: \[ 3a - 2a - 3a - a = (3 - 2 - 3 - 1)a = -3a \]

   • Now combine the constants: \[ 6 + 2 + 3 = 11 \]

3. Put it all together: \[ -3a + 11 \]

Thus, the simplified expression is: \[ \boxed{-3a + 11} \]