I am having problems center text that has been aligned. For some reason the second align is not centered. Here is an image of the output.
Below is my code...
words
\begin{align*}
1&=ak_1+bl_1\\
n&=n(ak_1+bl_1)\\
&=nak_1+nbl_1\\
&=ak_n+bl_n\\
\end{align*}
words
\begin{align*}
n&=ak_n+bl_n\\
&=ak_n+abx+bl_n-abx\\
&=a(k_n+bx)+b(l_n-ax)\\
&=ar+bs&\\
\end{align*}
more words
You have an improper & in the last line of the second alignment, which sets up a second set of alignments; those columns are empty, but the space between the first and the second set is accounted for.
You also have trailing \\ that should be removed.
\documentclass{article}
\usepackage{amsmath}
\usepackage{showframe} % just for the example
\begin{document}
words
\begin{align*}
1&=ak_1+bl_1\\
n&=n(ak_1+bl_1)\\
&=nak_1+nbl_1\\
&=ak_n+bl_n\\
\end{align*}
words
\begin{align*}
n&=ak_n+bl_n\\
&=ak_n+abx+bl_n-abx\\
&=a(k_n+bx)+b(l_n-ax)\\
&=ar+bs&\\
\end{align*}
more words
\end{document}
\documentclass{article}
\usepackage{amsmath}
\usepackage{showframe} % just for the example
\begin{document}
words
\begin{align*}
1&=ak_1+bl_1\\
n&=n(ak_1+bl_1)\\
&=nak_1+nbl_1\\
&=ak_n+bl_n
\end{align*}
words
\begin{align*}
n&=ak_n+bl_n\\
&=ak_n+abx+bl_n-abx\\
&=a(k_n+bx)+b(l_n-ax)\\
&=ar+bs
\end{align*}
more words
\end{document}
The frame is just for demonstration purposes. Don't load the showframe package yourself.
A mentioned in my comment, the last line in your aligned equations have surplus \\- Also in secon groupu of equations is one ampersund to much ... Try
\documentclass{article}
\usepackage{mathtools}
\usepackage{lipsum}
\begin{document}
\lipsum[2]
\begin{align*}
1 & = ak_1+bl_1 \\
n & = n(ak_1+bl_1) \\
& = nak_1+nbl_1 \\
& = ak_n+bl_n
\end{align*}
\lipsum[2]
\begin{align*}
n & = ak_n+bl_n \\
& = ak_n+abx+bl_n-abx \\
& = a(k_n+bx)+b(l_n-ax) \\
& = ar+bs
\end{align*}
\lipsum[2]
\end{document}
\\in your equations. They introduce additional vertical space shich seems to be your problem.. – Zarko May 20 '16 at 17:08&\\in the second alignment: remove it. – egreg May 20 '16 at 17:11\documentclass{...}, the required\usepackage's,\begin{document}, and\end{document}. That may seem tedious to you, but think of the extra work it represents for TeX.SX users willing to give you a hand. Help them help you: remove that one hurdle between you and a solution to your problem. – samcarter_is_at_topanswers.xyz May 20 '16 at 17:11&in the final line of the secondalign*environment supposed to achieve? – Mico May 20 '16 at 17:11