$$
      \begin{equation}
      \begin{aligned}[t]
      a & = & b & + & c \\
      d & = & e & + & f \\
      g & = & h & + & i
      \end{aligned}
      \begin{aligned}[b]
      a & = & b & + & c \\
      d & = & e & + & f \\
      g & = & h & + & i
      \end{aligned}
      \end{equation}
$$
