By symmetry, we only need to consider the case x⩾a. At this time,
xyz=a+b+c⩽3a⩽3x
Thus,
yz⩽3
Therefore,
(y,z)=(1,1),(2,1),(3,1)
When (y,z)=(1,1), a+b+c=x and x+2=abc, thus
abc=a+b+c+2
If c⩾2, then
a+b+c+2⩽3a+2⩽4a⩽abc
Equality holds if and only if a=b=c=2.
If c=1, then
ab=a+b+3
(a−1)(b−1)=4
(a,b)=(5,2),(3,3)
When (y,z)=(2,1), 2abc=2x+6=a+b+c+6, similar discussion shows that c=1, thus
(2a−1)(2b−1)=15
We get
(a,b)=(3,2)
When (y,z)=(3,1), 3abc=3x+12=a+b+c+12, similarly, there is no solution in this case.
In summary, we have
=(a,b,c,x,y,z)(2,2,2,6,1,1),(5,2,1,8,1,1),(3,3,1,7,1,1)(3,2,1,3,2,1),(6,1,1,2,2,2),(8,1,1,5,2,1)(7,1,1,3,3,1)