Question Number 151028 by kalenis last updated on 17/Aug/21
Answered by amin96 last updated on 17/Aug/21
$$\begin{cases}{{x}+{y}−{z}=\mathrm{7}\:\:\:\:\:−}\\{{x}−{y}+\mathrm{2}{z}=\mathrm{3}}\\{\mathrm{2}{x}+{y}+{z}=\mathrm{9}}\end{cases}\Rightarrow\begin{cases}{\mathrm{2}{x}+{z}=\mathrm{10}}\\{\mathrm{10}+{y}=\mathrm{9}}\end{cases}\:\Rightarrow\begin{cases}{\mathrm{2}{x}+{z}=\mathrm{10}}\\{{y}=−\mathrm{1}}\end{cases} \\ $$$$\begin{cases}{{x}−{z}=\mathrm{8}}\\{{x}+\mathrm{2}{z}=\mathrm{2}}\end{cases}\:\:\begin{cases}{\mathrm{2}{x}−\mathrm{2}{z}=\mathrm{16}}\\{{x}+\mathrm{2}{z}=\mathrm{2}}\end{cases}\Rightarrow\mathrm{3}{x}=\mathrm{18}\:\:{x}=\mathrm{6} \\ $$$${x}−{z}=\mathrm{8}\:\:\Rightarrow\:\:{z}=−\mathrm{2}\:\:\:\:\:{answer}\:\:\left(\mathrm{6};\:\:−\mathrm{1};\:\:−\mathrm{2}\right) \\ $$