Is the Intersection of Subrings of R a Subring of R?

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1. The Problem

If S and T are subrings of a ring R, show that S intersects T, is a subring of R.




The Attempt at a Solution



I don't know how to go about answering this question.
 
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What are the requirements for a subset of R to be a subring?
 
The following axioms must be satisfied
a) (for all or any) x,y E R implies x+(-y) E R
b) (for all or any) x,y E R implies xy E R ( R is closed under mulitplication)

The above are the requirements for a subring to be valid.

This is something i got from wikipedia:

Let R be a ring. Any intersection of subrings of R is again a subring of R. Therefore, if X is any subset of R, the intersection of all subrings of R containing X is a subring S of R. S is the smallest subring of R containing X. ("Smallest" means that if T is any other subring of R containing X, then S is contained in T.) S is said to be the subring of R generated by X. If S = R, we may say that the ring R is generated by X.

So then does S=T?
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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