Expanding the expression:
4(a^2 - 2a + 1) + (6a - 12 - a^2) -13
Simplify further:
4a^2 - 8a + 4 + 6a - 12 - a^2 - 13
Combine like terms:
3a^2 - 2a - 21
Therefore, the simplified expression is 3a^2 - 2a - 21.
Expanding the expression:
4(a^2 - 2a + 1) + (6a - 12 - a^2) -13
Simplify further:
4a^2 - 8a + 4 + 6a - 12 - a^2 - 13
Combine like terms:
3a^2 - 2a - 21
Therefore, the simplified expression is 3a^2 - 2a - 21.