10. Let the quadratic equation in $x$ be
$$
x^{2}+2 k x+\frac{1}{4}-k=0
$$

has two real roots. Then the range of values for $k$ is $\qquad$.
10. $k \geqslant \frac{\sqrt{2}-1}{2}$ or $k \leqslant-\frac{\sqrt{2}+1}{2}$.

Since the equation $x^{2}+2 k x+\frac{1}{4}-k=0$ has two real roots, then $\Delta=4 k^{2}-4\left(\frac{1}{4}-k\right) \geqslant 0$.
Solving this, we get $k \geqslant \frac{\sqrt{2}-1}{2}$ or $k \leqslant-\frac{\sqrt{2}+1}{2}$.