A streamgraph visualization shows two layers $f_1(x) = x^2$ and $f_2(x) = x$. To minimize 'wiggle', the baseline $b(x)$ is calculated as $b(x) = -\frac{1}{2}(f_1(x) + f_2(x))$. What is the vertical position of the bottom of the first layer $f_1$ at $x=2$?