Complex Numbers And Quadratic Equations question 699

Question: If $ z_1,z_2 $ are the roots of the quadratic equation $ az^{2}+bz+c=0 $ such that $ Im(z_1,z_2)\ne 0 $ then

Options:

A) a, b, c are all real

B) at least one of a, b, c is real

C) at least one of a, b, c is imaginary

D) all of a, b, c are imaginary

Show Answer

Answer:

Correct Answer: C

Solution:

Since $ az^{2}+bz+c=0 $ …. (1) and $ z_1,z_2 $ (roots of (1)) are such that Im $ (z_1z_2)\ne 0 $ . Now, $ {z_1}andz_2 $ are not conjugates of each other Complex roots of (1) are not conjugate of each other Coefficient a, b, c cannot all be real at least one of a, b, c, is imaginary.