(-3a+3y)+(a-2y)

To simplify the expression \((-3a + 3y) + (a - 2y)\), we can combine like terms.

1. Group the terms involving \(a\) and the terms involving \(y\): \[ (-3a + a) + (3y - 2y) \]

2. Now, simplify each group:

   • For the \(a\) terms: \(-3a + a = -2a\)
   • For the \(y\) terms: \(3y - 2y = 1y\) or just \(y\)

3. Combine the results: \[ -2a + y \]

So, the simplified expression is: \[ -2a + y \]