# [texhax] Exempting an equation from alignment

Soeren D. Schulze soeren.d.schulze at gmx.de
Sun Aug 5 11:42:10 CEST 2007

E. Krishnan wrote:
> On Sat, 4 Aug 2007, Soeren D. Schulze wrote:
>
>> I need to format something like this (whitespace-formatted here):
>>
>>   x (x + 1) = 0
>> => x_1 = 0
>>       x + 1 = 0
>> => x_2 = -1
>>
>> This is quite a stupid example, but the first and the third line are
>> supposed to be aligned (equal signs below each other), whereas the
>> second and the fourth line are not supposed to influence the alignment,
>
>
> Will this do?
>
> $$\setlength{\arraycolsep}{0pt} > \begin{array}{rr@{\;}l} > & x(x + 1) & = 0\\ > \Rightarrow & \multicolumn{2}{l}{x_1=0}\\ > & x+1 & = 0\\ > \Rightarrow & \multicolumn{2}{l}{x_2=-1} > \end{array}$$

The array' command is exactly what I was looking for, thank you
Is there any reason to prefer either array' or align' in cases where
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