#### Answer

a = $-\frac{3}{2}$

#### Work Step by Step

4(3 - a) - (6a + 9) = -12a
Distribute:
12 - 4a - 6a - 9 = -12a
Combine like terms:
-10a + 3 = -12a
Add 12a to both sides:
2a + 3 = 0
Subtract 3 from both sides:
2a = -3
Divide both sides by 2:
a = $-\frac{3}{2}$