Question

Please solve this fast.​

Answer 1

- 24 - 70i

Explanation:

Given

(
`√(5)` - 7i)²

= (
`√(5)` - 7i)(
`√(5)` - 7i)

= 5 - 7
`√(5)` i - 7
`√(5)` i + 49i² ( note that i² = - 1 )

= 5 - 14
`√(5)` i - 49

= - 44 - 14
`√(5)` i

Answer 2

Explanation:

(a - b)² = a² - 2ab + b²

`[√(5) - 7i]^(2)= (√(5))^(2) - 2*√(5)*7i + (7i)^(2)\\\\\\= 5 - 14i√(5)+7^(2)*i^(2)]]= 5 -14i√(5) +49 * -1\\\\= 5 -14i√(5) - 49\\\\= -44 - 14i√(5)`