Theorem (1): Let R be a commutative ring with identity, let a be a nonzero element
of R. Then there exists a multiplicative closed set Sa = {a′εR:a=aa′} of the ring R with
ann (a) ∩ Sa =ɸ.
There exists a′εR, a′
≠0 such that:
a′b = a′
a [2] (4)
In this work we use,
ann(a) = { xεR : ax = 0 }