Evaluate:

It is given in the question that,

=


=


=


=


=


= [- 1 – 1]3


= (- 1)3 [1 + i]3


= - [13 + i3 + 3 × 1 × i (1 + i)]


= - [1 + i3 + 3i + 3i2]


= - [1 – i + 3i – 3]


= - [- 2 + 2i]


= 2 – 2i


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