Algebra

First, let's move all terms to one side and set up a quadratic equation. We have

$-10x^2+kx-23=0$

Now, in order for the roots to be nonreal, the descriminant must be less than 0. Thus, we can write the equation

$k^2-920 < 0$

Now, we simply solve for k. We have

$k^2<920\\ $

Since we must square k, there are two restrictive intervals for k. We have

$-2\sqrt{230} <2\sqrt{230}$

So our final answer for k is

$-2\sqrt{230} <2\sqrt{230}$

Thanks! :)