Question

Решите систему уравнений. По примеру во второй фотографии.

Answer 1

$\Delta = \begin{vmatrix} 2&1&1 \\ 3&-1&0 \\ 0&4&3 \end{vmatrix} = -6+12-9 = -3, \\ \Delta_x = \begin{vmatrix} 7&1&1 \\ 6&-1&0 \\ 5&4&3 \end{vmatrix} = -21+24+5-18 = -10, \\ \Delta_y = \begin{vmatrix} 2&7&1 \\ 3&6&0 \\ 0&5&3 \end{vmatrix} = 36+15-63 = -12, \\ \Delta_z = \begin{vmatrix} 2&1&7 \\ 3&-1&6 \\ 0&4&5 \end{vmatrix} = -10+84-48-15 = 11;$
$x= \frac{\Delta_x}{\Delta} = \frac{-10}{-3} = 3\frac{1}{3}, y= \frac{\Delta_y}{\Delta} = \frac{-12}{-3} = 4, z= \frac{\Delta_z}{\Delta} = \frac{11}{-3} = -3\frac{2}{3} .$