# System of equations with left curly bracket

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

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


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?

• You should consider the package systeme. – F. Pantigny Feb 28 at 11:17
• Welcome to TeX.SE. – Mico Feb 28 at 11:27
• @F.Pantigny This seems to be nice. However, if I have, for example, a left hand side as $z_k'$ it is not displayed. – C.D. Feb 28 at 11:34

I suggest you (a) employ an aligned environment instead of an array enviroment and (b) change both instances of =& to &=.
\documentclass{article}
\left\{ \begin{aligned} f(x) &= x^2+\ldots\\ g(x) &= x^3+\ldots \end{aligned} \right.