Question

Помогите пожалуйста решить ​

Answer 1

Ответ:

$1)\ \ \left|\begin{array}{cccc}6&3&5&5\\2&3&5&2\\5&5&5&2\\2&5&3&3\end{array}\right|=\ 3str\leftrightarrow 4str\ =-\left|\begin{array}{cccc}6&3&5&5\\2&3&5&2\\2&5&3&3\\5&5&5&2\end{array}\right|=-1*2str+3str=$

$=\left|\begin{array}{cccc}6&3&5&5\\2&3&5&2\\0&2&-2&1\\5&5&5&2\end{array}\right|=\ 1str\leftrightarrow 4str\ =\left|\begin{array}{cccc}5&5&5&2\\2&3&5&2\\0&2&-2&1\\6&3&5&5\end{array}\right|=-3*2str+4str\ =$

$=\left|\begin{array}{cccc}5&5&5&2\\2&3&5&2\\0&2&-2&1\\0&-6&-10&-1\end{array}\right|=5\cdot \left|\begin{array}{cccc}1&1&1&\frac{2}{5}\\2&3&5&2\\0&2&-2&1\\0&-6&-10&-1\end{array}\right|=\ -2*1str+2str\ =$

$=5\cdot \left|\begin{array}{cccc}1&1&1&\ \frac{2}{5}\\0&1&3&\frac{6}{5}\\0&2&-2&1\\0&-6&-10&-1\end{array}\right|=-2*2str+3str\ ;\ 6*2str+4str\ =\\\\\\=5\cdot \left|\begin{array}{cccc}1&1&1&\ \frac{2}{5}\\0&1&3&\frac{6}{5}\\0&0&-8&-\frac{7}{5}\\0&0&-16&2\end{array}\right|=-2*3str+4str\ =5\cdot \left|\begin{array}{cccc}1&1&1&\ \frac{2}{5}\\0&1&3&\frac{6}{5}\\0&0&-8&-\frac{7}{5}\\0&0&0&\frac{24}{5}\end{array}\right|=$

$=5\cdot 1\cdot 1\cdot (-8)\cdot \dfrac{24}{5}=-192$

$2)\ \ \left|\begin{array}{cccc}6&3&5&5\\2&3&5&2\\5&5&5&2\\2&5&3&3\end{array}\right|=6\cdot \left|\begin{array}{cccc}3&5&2\\5&5&2\\5&3&3\end{array}\right|-3\cdot \left|\begin{array}{cccc}2&5&2\\5&5&2\\2&3&3\end{array}\right|+5\cdot \left|\begin{array}{cccc}2&3&2\\5&5&2\\2&5&3\end{array}\right|-\\\\\\-5\cdot \left|\begin{array}{cccc}2&3&5\\5&5&5\\2&5&3\end{array}\right|=6\cdot \Big(3(15-6)-5(15-10)+2(15-25)\Big)-$

$-3\cdot \Big(2(15-6)-5(15-4)+2(15-10)\Big)+5\cdot \Big(2(15-10)-3(15-4)+2(25-10)\Big)-\\\\-5\cdot \Big(2(15-25)-3(15-10)+5(25-10)\Big)=\\\\=6\cdot (-18)-3\cdot (-27)+5\cdot 7-5\cdot 40=-192$