# [Tex/LaTex] Align multi-line equations with implies

alignequations

I'd like to obtain something like,

   A + B = C + D
=> A + B + E = C + D + E
=> A + E = C + D + E - B
= C + F - B
= G - B
=> A + E + B = G


I've tried fiddling with align and alignat, but couldn't get what I want. The only way that I could think of is to use explicit value for horizontal space, which is very messy. Another solution is to use phantom, but again that seems cumbersome.

Any help regarding this is appreciated!

alignat(*) works with the proper number of columns, and a \quad to give it some air:

\documentclass[]{article}
\usepackage{amsmath}

\begin{document}

\begin{alignat*}{2}
& & A + B & = C + D\\
\Rightarrow\quad & & A + B & + E = C + D + E\\
\Rightarrow\quad & & A + E & = C + D + E - B\\
& &       & = C + F - B\\
& &       & = G - B\\
\Rightarrow\quad & & A + E & + B = G
\end{alignat*}
\end{document}


Here I've tried to reproduce your example as closely as possible. Personally, I'd align on the "=" sign, if you want that, just move the "&" to before the "=".