X 1+2y= 17。
For X 1+2y= 1.
There is a special solution X 1=- 1, y= 1,
So for X 1+2y= 17.
There is a special solution X 1=- 17, y= 17,
So for X 1+2y= 17.
There are solutions X 1=- 17-2t, y= 17+t,
So x2+x3 =17+t.
Let X3=T
Then x2 =17+t-t.
X3=T
And because X 1=- 17-2t.
So the integer solution is
X 1= - 17-2t
X2= 17+t-T
X3=T
Integer classification
With 0 as the boundary, integers are divided into three categories:
1, a positive integer, that is, an integer greater than 0, such as 1, 2, 3…
2,0 is neither a positive integer nor a negative integer (0 is an integer).
3. Negative integers, that is, integers less than 0, such as-1, -2, -3…