How do I align equations in the system? LaTeX

Question

How to equalize equations in the system by columns of unknown quantities.

For example

  x1-2*x2     =4
     6*x2  -x3=7
3*x1     +8*x3=2

Answer 1

You can use the package systeme:

\documentclass{article}
\usepackage{systeme}
\begin{document}
\systeme{
  x_1-2x_2     =4 ,
     6x_2  -x_3=7 ,
3x_1     +8x_3=2}
\end{document}