$$ \begin{align*} \textbf{Izračunaj ove izraze } \&\ a) \frac{ 1 x^{2}+ 2 x - 42 }{(x- 1 )^{2}}= 0 \&b) \frac{ 42 x^{2}+ 5 x - 2 }{(x- 2 )^{2}}= 0 = 0 \&c) \binom{21}{x}\sum_{x}^{x+12} ( X+2X - 2x \cdot 2 ) \&d) X^{3} - 2 X - 2 + 42 X^{2}-\frac{1}{ 2 } X^{2} = 0 \&\end{align*} $$