# Adding right brace and equation number

I have an eqnarray that consists of 4 lines. I would like to have a right brace } that spans the last two lines with equation number, first equation with equation number and second equation with nonumber. Some brief text explaining these two parts of the equation. Something like

a=b   (1)
c=d
x=y}
}  (2)
z=t}

• could you use align for equations? Commented Feb 18, 2016 at 14:09
• yes I could use align Commented Feb 18, 2016 at 14:10
• Do all four equations have to be aligned at the equal sign? Commented Feb 18, 2016 at 14:16
• yes. They have to be aligned at the equal sign? I forgot to write. Thanks Commented Feb 18, 2016 at 14:18
• potential duplicate: Combining split and rcases Commented Feb 18, 2016 at 14:34

Here is a quick solution. It uses a manually set size of the brace. Maybe someone can provide something more robust.

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\begin{align}
a &{} = b \\
c &{} = d \nonumber \\
\begin{split}
x &{} = y \\
z &{} = t