Question

Please help simplify and write your answer in the form a + bi

Answer 1

Answer:

$2 - 4i$

Step-by-step explanation:

$\frac{10}{1 + 2i} \\ \\ = \frac{10}{1 + 2i} \times \frac{1 - 2i}{1 - 2i} \\ \\ = \frac{10(1 - 2i)}{ {1}^{2} - {(2i)}^{2} } \\ \\ = \frac{10 - 20i}{ {1} - {4i}^{2} } \\ \\ = \frac{10 - 20i}{ {1} - {4( - 1)} } \\ ( \because \: {i}^{2} = - 1) \\ \\ = \frac{10 - 20i}{1 + 4} \\ \\ = \frac{5(2 - 4i)}{5} \\ \\ = 2 - 4i$