P
pnh_hpn


Giải Hệ PT 3 Ẩn
[tex]\left\{ \begin{array}{l} x+y+z = 9 \\ \frac{1}{x}+ \frac{1}{y}+ \frac{1}{z}=1 \\ xy+yz+xz=27 \end{array} \right.[/tex]
[tex]\left\{ \begin{array}{l} x+y+z = 9 \\ \frac{1}{x}+ \frac{1}{y}+ \frac{1}{z}=1 \\ xy+yz+xz=27 \end{array} \right.[/tex]