For those values of "k" for which the discriminant d = b^2 - 4ac is positive (I refer to the general form of quadratic equation ax^2 + bx + c = 0.) In your case the discriminant is k^2 -4*2*(-3) = k^2 + 24. This expression is positive for all and any values of "k": it is the sum of a square and the positive number. Hence, the given equation has 2 (two) different real solutions at any value of k.