Question

The equation 2x^2+5kx+k=0, where k is a constant has no real roots. Find possible values of k

Answer 1

Explanation:

What do you mean "no real roots" ?

if I understand correctly we have

2x² + 5kx + k = 0

the solutions for such a quadratic equating are

x = (-b ± sqrt(b² - 4ac))/(2a)

a = 2

b = 5k

c = k

so, we get

x = (-5k ± sqrt(25k² - 8k))/4

why would that have no real solutions ?

e.g. k = 2

x = (-10 ± sqrt(100 - 16))/4 = (-10 ± sqrt(84))/4

since the sqrt is a little bit bigger than 9 we get 2 negative solutions for x. but still real.

I don't understand what your need here.