If the natural number x

If the natural number x

Because x, y, Z are natural numbers, a is an integer, and there are
x≥1,1≥1/x
y≥2,1/2≥1/y
z≥3,1/3≥1/z
0<1/x+1/y+1/z≤11/6<2
So a = 1
So x > 1 (if x = 1,1 / x + 1 / y + 1 / Z > 1)
If x > 2, then x ≥ 3
Then 1 / 3 ≥ 1 / x, 1 / 4 ≥ 1 / y, 1 / 5 ≥ 1 / Z
1/x+1/y+1/z≤47/60<1
Not established
So x = 2,1 / x = 1 / 2
If Y > 3, y ≥ 4
Then 1 / 4 ≥ 1 / y, 1 / 5 ≥ 1 / y
1/y+1/z≤9/20<1/2
1/x+1/y+1/z<1
Not established
So y = 3
From the solution of 1 / x + 1 / y + 1 / z = 1, z = 6 is obtained
So x = 2, y = 3, z = 6
xyz=36