System of equations with left curly bracket

Question

For a system of equations, I would like to have a notation with a left curly bracket. Usually, I am using

\begin{equation}
\left\{ 
\begin{array}{ll} 
f(x)=&x^2+\ldots\\
g(x)=&x^3+\ldots\end{array}\right.
\end{equation}

But this makes a strange empty space between the "=" and the right-hand sides which i do not like since.

Is there a way to improve this easily?

Answer 1

I suggest you (a) employ an aligned environment instead of an array enviroment and (b) change both instances of =& to &=.

\documentclass{article}
\usepackage{amsmath} % for 'aligned' env.
\begin{document}

\begin{equation}
\left\{ \begin{aligned} 
  f(x) &= x^2+\ldots\\
  g(x) &= x^3+\ldots
\end{aligned} \right.
\end{equation}
\end{document}