ay-3y-4a+12

To simplify the expression \( ay - 3y - 4a + 12 \), you can rearrange and group the terms:

1. Group the terms involving \( a \) and the terms with \( y \): \[ (ay - 3y) + (-4a + 12) \]

2. Factor out the common terms from each group: \[ y(a - 3) + 4(-a + 3) \]

3. Reorganizing gives: \[ y(a - 3) - 4(a - 3) \]

4. You can factor out \( (a - 3) \): \[ (a - 3)(y - 4) \]

Thus, the expression \( ay - 3y - 4a + 12 \) simplifies to \( (a - 3)(y - 4) \).