Since this is a 1st order PHI, it has no further iterations. Once is all unity needs to authenticate itself.
It also has no relationship with any other value, so there is no need to approximate its solution by dividing some other number into unity!
Hence, all we get is...
X = 1
Subtracting 1 from both sides, we get...
A linear polynomial in one unknown: X − 1 = 0
Continue with this brief overview, here...