What does the ideal $I$ of $\mathbb{Z}[X]$ generated by $x$ and $2$ look like?

Question

What does the ideal $I$ of $\mathbb{Z}[X]$ generated by $x$ and $2$ look like?

I don't know how to put it into terms of more explicit set notation

Answer 1

Every element of $I=(2,x)$ will be exactly the same as any polynomial in $\mathbb{Z}[X]$, except for the constant coefficient being necessarily even.

Answer 2

$I=(x,2)=\{xf+2g:f,g\in\mathbb{Z}[X]\}$