Question

va rog ajutor,nu știu cum se rezolva ​

Answer 1

$\it \begin{vmatrix}-1&4\\ 8&-25\end{vmatrix}=-1\cdot(-25)=8\cdot4=25-32=-7$

$\it \begin{vmatrix}4&-1&2\\3&5&-1\\2&1&0\end{vmatrix}\ \stackrel{(\ell_1+2\ell_2)}{=}\begin{vmatrix}10&9&0\\3&5&-1\\2&1&0\end{vmatrix}=\begin{vmatrix}10&9\\2&1\end{vmatrix}=10-18=-8$

Expresia  devine:

-7-6·(-8)+2·5=-7+48+10=51