(1)a = b + c d = e + f g = h + ia = b + c d = e + f g = h + i \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}