Given that: ∣z−2−2i∣≤1 which represents a circle with centre at (2,2) and radius =1.
Now ∣3iz+6∣=∣3i(z−2i)∣=∣3i∣∣z−2i∣
As we know that, [∣z1z2∣=∣z1∣∣z2∣]
From tha diagram we can see that, ∣3iz+6∣=3∣z−2i∣ is maximum at z=3+2i because a point on the circle, which has maximum distance from (0,2) is (3,2).

So, a=3&b=2
⇒a+b=5