# How to get align environment in the same line as text [duplicate]

I would like to have an align environment which is not automatically written in a new line. For example in the following code, the formulas should appear in the same line as the itemize-dot or the Proof. :

\documentclass[10pt,a4paper]{article}
\usepackage[latin1]{inputenc}
\usepackage{amsmath}
\usepackage{amsthm}
\begin{document}

\begin{itemize}
\item
\begin{align*}
x & = 0 \\
y & = 15
\end{align*}
\end{itemize}

\begin{proof}
\begin{align*}
x & = 0 \\
y & = 15
\end{align*}
\end{proof}
\end{document}


I know that I could use $\displaystyle x=0$ for single lines but the align environment is clearly better when aligning more than one line of formulas. Does anybody have an idea?