3b-5a-(b-(За-b)=

To simplify the expression \( 3b - 5a - (b - (a - b)) \), let's break it down step by step.

1. Start with the inner expression \( a - b \):

   • Therefore, \( b - (a - b) = b - a + b = 2b - a \).

2. Substitute \( 2b - a \) back into the original expression: \[ 3b - 5a - (2b - a) \]

3. Now distribute the negative sign: \[ 3b - 5a - 2b + a \]

4. Combine like terms:

   • For \( b \) terms: \( 3b - 2b = 1b = b \)
   • For \( a \) terms: \( -5a + a = -4a \)

So the final simplified expression is: \[ b - 4a \]

If you need further assistance or have more questions, feel free to ask!