Giải hệ phương trình: 4x + y - 3z = 11; 2x - 3y + 2z = 9; x + y + z = -3

* Hướng dẫn giải

$\left\{\begin{array}{l}4x+y-3z=11\\ 2x-3y+2z=9\\ x+y+z=-3\end{array}\right.\iff \left\{\begin{array}{l}4x+y-3z=11\\ 7y-7z=-7\\ x+y+z=-3\end{array}\right.\iff \left\{\begin{array}{l}4x+y-3z=11\\ y-z=-1\\ -3y-7z=23\end{array}\right.$

$\left\{\begin{array}{l}4x+y-3z=11\\ y-z=-1\\ -10z=20\end{array}\right.\iff \left\{\begin{array}{l}4x+y-3z=11\\ y-\left(-2\right)=-1\\ z=-2\end{array}\right.\iff \left\{\begin{array}{l}4x+\left(-3\right)-3.\left(-2\right)=11\\ y=-3\\ z=-2\end{array}\right.\iff \left\{\begin{array}{l}x=2\\ y=-3\\ z=-2\end{array}\right..$