\[\boxed{\mathbf{81.}}\]
\[\textbf{а)}\ y = x^{2} - 5|x - 1| + 1\]
\[\textbf{б)}\ y = \left| x^{2} - 3x + 2 \right| + 2x - 3\]
\[\textbf{в)}\ y = (x + 1)(|x| - 2)\]
\[\textbf{г)}\ y = \left| x^{2} + 3x - 2 \right| - |5x - 2|\]
\[\textbf{д)}\ y = \frac{2x - 6}{|3 - x|};\ \ x \neq 3\]
\[\textbf{е)}\ y = \frac{2|x| + 1}{2 - x};\ \ \ x \neq 2\]
\[\textbf{ж)}\ y = \sin{(|x|)}\]
\[\textbf{з)}\ y = \left| \cos\left( |x| \right) \right|\]