Question

Which of the following is the conjugate of a complex number with 3 as the real part and –5i as the imaginary part?

Answer 1

Answer: Our required conjugate of a complex number is 3+5i.

Step-by-step explanation:

Since we have given that

There is a complex number which has 3 as the real number and -5i as the imaginary part.

So, our required complex number is 3-5i.

We need to find the conjugate of a complex number will be

3+5i as in case of conjugation we only change the sign of imaginary number .

So, our required conjugate of a complex number is 3+5i.

Answer 2

3 + 5i 

(3 - 5i)(3 + 5i) = 
9 + 15i - 15i - 25i^2 = 
9 - 25 * -1 = 
9 + 25 = 
34 

or 
x = 3 + 5i 
x - 3 - 5i = 0 

x = 3 - 5i 
x - 3 + 5i = 0 

(x - 3 - 5i)(x - 3 + 5i) = 0 
x^2 - 3x + 5xi - 3x + 9 - 15i - 5xi + 15i - 25i^2 = 0 
x^2 - 6x + 34 = 0
Answer= 3+5i