Question

kindly see the attached file and evaluate it
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Answer 1

YOUR SOLUTION IS IN PICTURE

Answer 2

$\large\bf{Solution:}$

$(1 + 2i) {}^{ - 3} \\ = \frac{1}{ {(1 + 2i)}^{3} } \\ = \frac{1}{ {1}^{3} + (2i) {}^{ 3} + 3.1.2i(1 + 2i) } \\ = \frac{1}{1 + ( - 8i) + 6i(1 + 2i) } \\ = \frac{1}{1 + - 8i + 6i + 12i {}^{2} } \\ = \frac{1}{1 - 2i - 12 } \\ = \frac{1}{ - 11 - 2i}$

= 1/-11-2i × -11+2i/-11+2i

= -11+2i/-11²-(2i)²

= -11+2i/121+4

= -11+2i/125

= -11/125 + 2i/125