Solution
= Solution
For arbitrary $y\in\mathbb R^2$, the <continuous map> $g_y(x)=g(x)-y$ satisfies $\|g_y(x)-x\|\leq K+\|y\|$. Applying the preceding <Brouwer fixed-point theorem> argument with this positive bound gives $g_y(t)=0$. Hence $g(t)=y$, and \b[$g$ is surjective].