If for the complex numbers z satisfying | z $$-$$ 2 $$-$$ 2i | $$\le$$ 1, the maximum value of | 3iz + 6 | is attained at a + ib, then a + b is equal to ______________.

A point z moves in the complex plane such that $$\arg \left( {{{z - 2} \over {z + 2}}} \right) = {\pi \over 4}$$, then the minimum value of $${\left| {z - 9\sqrt 2 - 2i} \right|^2}$$ is equal to _______________.

Let z₁ and z₂ be two complex numbers such that $$\arg ({z_1} - {z_2}) = {\pi \over 4}$$ and z₁, z₂ satisfy the equation | z $$-$$ 3 | = Re(z). Then the imaginary part of z₁ + z₂ is equal to ___________.

The least positive integer n such that $${{{{(2i)}^n}} \over {{{(1 - i)}^{n - 2}}}},i = \sqrt { - 1} $$ is a positive integer, is ___________.