I am currently trying to get the align environment to work as I want it to work.
\begin{align}
&& a \cdot c + b &= 0\\
\Leftrightarrow && a \cdot c &= -b\\
\end{align}
This code will align the equivalent sign in the middle of the left half and the equal sign in the middle of the right half. What I actually want is that the equivalent sign is on the outer left of the page and the formula is in the middle of the remaining page. How can this be done and is this even encouraged? Or is there a better way to align formula with equivalent and equal signs?