Simplify each of the following and express it in the form (a + ib) :

(1 + 2i)–3


Given: (1 + 2i)-3

Above equation can be re – written as



Now, rationalizing




We know that,


(a – b)3 = a3 – 3a2b + 3ab2 – b3


(a + b)3 = a3 + 3a2b + 3ab2 + b3




[∵i2 = -1]






[∵i2 = -1]





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