# center align equation

I try to align a multiline equation, but im getting a large space.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{mathtools}
\begin{document}

\begin{align}
AAAAAA &\,  yyyyy &=& bbbbbb    \\
A    &\,     y  &=&    b  \notag
\end{align}
\end{document}


I would like the letters in the second line to be in the center of the above.

EDIT:

The first line stands for a Matrix equation. With Micos solution i now got:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
$$\begin{array}[t]{c @{\,} c @{{}={}} c} \begin{pmatrix} 1 & 0 \\ 0 & 1 \\ 0 & 0 \\ \end{pmatrix} & \begin{pmatrix} x\\ y\\ \end{pmatrix} & \begin{pmatrix} x\\ y \\ 0\\ \end{pmatrix} \\ A & x & d \\ \end{array}$$

\end{document}

• for example the single letter 'A' in the second line should be center to 'AAAAA' from the first line. Nov 6 '14 at 16:35
• Welcome to TeX.SE! Have you looked into using an array environment?
– Mico
Nov 6 '14 at 16:35
• no i havent, but thats not a math environment, right Nov 6 '14 at 16:41
• Actually, array is very much the math-mode equivalent of tabular.
– Mico
Nov 6 '14 at 16:46

You could try:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{mathtools}
\begin{document}
$$\begin{array}[t]{c @{\,} c @{{}={}} c} AAAAAA & yyyyy & bbbbbb \\ A & y & b \\ \end{array}$$
\end{document}


Addendum, to address the OP's follow-up query: To typeset the two versions of the matrix equation you've added to your initial query, I would use nearly the same code as given above, with the exception that I would replace @{\,} with @{} as the separator between the first and second column of the array. This is because, in my not-so-humble opinion..., the spacing between matrix-like environment provided by the amsmath package (which provides the pmatrix environments) is a bit excessive, especially so for the case at hand. (If you do want the default spacing of the amsmath package, just keep the @{\,} inter-column specification as per the initial answer.)

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{mathtools}
\begin{document}
$$\begin{array}[t]{c @{} c @{{}={}} c} \begin{pmatrix} 1 & 0 \\ 0 & 1 \\ 0 & 0 \\ \end{pmatrix} & \begin{pmatrix} x\\ y\\ \end{pmatrix} & \begin{pmatrix} x\\ y \\ 0\\ \end{pmatrix} \\[4ex] A & x & d\\ \end{array}$$
\end{document}

• Of course mathtools is not necessary. Nov 6 '14 at 16:46
• thank you, that looks good. how can i change the vspace between first and second line? Nov 6 '14 at 16:56