Voici son code :
\begin{variations}
x & \mI & & 2 & &\pI\\
\filet\filet
-4 & & -~~ & \z & ~~- & \\
\filet
x-2 & & -~~ & \z & ~~+ & \\
\filet\filet
%------------------------------------------------------
-4(x-2) & & +~~ & \z & ~~- & \\
\end{variations}
Voici son code :
\begin{variations}
x & ~0 & & 2 & &\pI\\
\filet\filet
-4 & \bg & ~~-~~ & \l & ~~- & \\
\filet
x & \bg & + & \l & ~~+ & \\
\filet
x-2 & \bg & - & \z & ~~+ & \\
\filet\filet
%------------------------------------------------------
\frac{-4}{x(x-2)} & \bg & + & \z & ~~- & \\
\end{variations}