Question

Simply the following: (2+5i)^2 - (2+i)​

Answer 1

- 23 + 19i

Explanation:

`(2 + 5i)^(2) - (2 + i) \\ \\ = {2}^(2) + {(5i)}^(2) + 2.2.5i - 2 - i \\ \\ = 4 + 25 {i}^(2) + 20i - 2 - i \\ \\ = 4 - 25 + 20i - 2 - i \\ ( \because \: {i}^(2) = - 1) \\ \\ 4 - 25 - 2 + 20i - i \\ \\ = - 23 + 19i`