## jkasdhk Group Title minimum possible value of K for which the equation 2x^2+6x+K=0 has complex roots? 2 years ago 2 years ago

1. mukushla

for having complex roots Discriminant of quadratic equation must be less than zero then what is result?

2. jkasdhk

its 9/2 (4.5)<0. Will the answer be 4?

3. UnkleRhaukus

$2x^2+6x+K=0$ has complex roots when the discriminate is <0 $\Delta=b^2-4ac$$=6^2-4\times1\times K$

4. UnkleRhaukus

because in the quadratic formula we have to take the square root of the discriminant , $x=\frac{-b\pm\sqrt\Delta}{2a}$

5. Callisto

Little correction for the above post... Δ=b^2 - 4ac = (6)^2 - 4(2)(K) < 0 Now you need to solve this: (6)^2 - 4(2)(K) < 0