Verified answer

2xy+yz=27

3yz-2xz=25

xz-xy=4

xz=4+xy

3yz-2(4+xy)=25

 3yz-2xy=33 

 3yz-2xy=33

2xy+yz=27

4yz=60  yz=15

xy=6

xz=10

y=15/z  15x/z=6 xz=10

x=6/15*z   x=10/z 

  6/15*z =10/z

(6/15*z^2-10)/z=0

(6/15*z^2-10)/z=0  

0.4*z^2-10=0

z^2=25

z=5 z=-5 

x=2 x=-2

y=3  y=-3  

x=2 y=3 z=5 

 x=-2 y=-3 z=-5