Here there is the command:
\begin{minipage}{0.5\linewidth}
\begin{equation}
y_1(x)=x^2
\end{equation}
\end{minipage}
\hspace{0.5cm}
\begin{minipage}{0.5\linewidth}
\begin{equation}
y_2(x)=2x+1
\end{equation}
\end{minipage}
best wishes
Antonio