How can I show that $\mathbb R [x]/(x^5+x-3)$ is not an Integral domain?
13981
Proof that every polynomial of odd degree has one real root
131082
Proof that $\mathbb R/[0,1]$ and $\mathbb R$ are homeomorphic
66272
Is there a common notion of $\mathbb{R}^n$, for non-integer $n$?
74330
$\mathbb{R}^n$ not homeomorphic to open subset of $\mathbb{R}^m$
151439
$\sqrt{1-x^2}$ is not a rational function
84148
Why is $\mathbb{R}^2$ not a subspace of $\mathbb{R}^3$?
39114
Prove that a set in $\mathbb R^3$ is not an algebraic set
102914
Integral domain that is not a factorization domain
57310
Prove $\mathbb{Z}$ is not a vector space over a field
92420
Characteristic of  a Non-unital Integral Ring
97782
Why are the domains for $\ln x^2$ and $2\ln x$ different?
158502
Showing $\sin(\bar{z})$ is not analytic at any point of $\mathbb{C}$
3037
Integral domain without unity has prime characteristic?
21843
Proving a function is not Riemann integrable
78950
Does this map extend to a unique automorphism of the polynomial ring of an integral domain?
146470
Show $\mathbb{Z}[\sqrt{6}]$ is a Euclidean domain
155604
Show that $k[x,y]/(xy-1)$ is not isomorphic to a polynomial ring in one variable.