Question

25 БАЛОВ ПОЖАЛУЙСТА!

Answer 1

$\displaystyle\left \{ {{x+y-3z=0} \atop {3x+2y+2z=-1}} \atop{x-y+5z=-2}} \right. \\\\\bigtriangleup=\left|\begin{array}{ccc}1&1&-3\\3&2&2\\1&-1&5\end{array}\right| =10+9+2+6+2-15=14\\\\\\\bigtriangleup_1=\left|\begin{array}{ccc}0&1&-3\\-1&2&2\\-2&-1&5\end{array}\right| =0-3-4-12-0+5=-14\\\\\\\bigtriangleup_2=\left|\begin{array}{ccc}1&0&-3\\3&-1&2\\1&-2&5\end{array}\right| =-5+18+0-3+4-0=14\\\\\\\bigtriangleup_3=\left|\begin{array}{ccc}1&1&0\\3&2&-1\\1&-1&-2\end{array}\right| =-4-0-1-0-1+6=0$

$\displaystyle\\x=\frac{\bigtriangleup_1}{\bigtriangleup} =\frac{-14}{14} =-1\\\\y=\frac{\bigtriangleup_2}{\bigtriangleup} =\frac{14}{14} =1\\\\z=\frac{\bigtriangleup_3}{\bigtriangleup} =\frac{0}{14} =0\\\\\textbf{(\emph{x,y,z})=(-1;1;0)}$