$$ \begin{align*} \textbf{Aufgabe} \&\quad a) (10 + 30) + (-81 + 5) = ? \&\quad b) \frac{-9 x^{2} + -81 x - 1}{(x - 8)^{2}} = ? \&\quad c) {6}^{2} + 3 \cdot -9 = ? \&\quad d) X^{3} - -81 X - -81 + 4 X^{2} - \frac{1}{1} X^{2} = 0 \\end{align*} $$