Question

${2}^{ - 3} \times {4}^{1}$
​

Answer 1

Let 20 - 21i = ( a + bi )² for (a,b)∈R => 20 - 21i = a² + (2ab)i + (b²)i² => 20 - 21i = (a² - b²) + ( 2ab)i. Equating equations: a² - b² = 20 2ab = -21 => b= -21/2a. Putting this in previous eqn., a² - 441/(4a²) = ...

Answer 2

Step-by-step explanation:

I hope that it is helpful to you