Question

X1+x2+x3=2 2x1-3x2+2x3=2 3x1-2x2+4x3=-5 как решить?

Answer 1

Метод Гаусса-Жордана
$(A|B)\rightarrow(E|X)\\\begin{cases}x_1+x_2+x_3=2\\2x_1-3x_2+2x_3=2\\3x_1-2x_2+4x_3=-5\end{cases}$
$\left(\begin{array}{ccc|c|c}1&1&1&2&\downarrow\\2&-3&2&2&-2\\3&-2&4&-5&-3\end{array}\right)\ \textgreater \ \left(\begin{array}{ccc|c|c}1&1&1&2&\\0&-5&0&-2&:-5\\0&-5&1&-11&\end{array}\right)\ \textgreater \ \\\left(\begin{array}{ccc|c|c}1&1&1&2&-1\\0&1&0&\frac{2}{5}&\updownarrow\\0&-5&1&-11&5\end{array}\right)\ \textgreater \ \left(\begin{array}{ccc|c|c}1&0&1&\frac{8}{5}&-1\\0&1&0&\frac{2}{5}&\\0&0&1&-9&\uparrow\end{array}\right)\ \textgreater \ \\\left(\begin{array}{ccc|c|c}1&0&0&\frac{53}{5}&\\0&1&0&\frac{2}{5}&\\0&0&1&-9&\end{array}\right)\\$
$X=\left(\begin{array}{c}x_1\\x_2\\x_3\end{array}\right)=\left(\begin{array}{c}\frac{53}{5}\\\frac{2}{5}\\-9\end{array}\right)$