Aligning Equations in LaTeX: Troubleshooting

[computer2012]

Hi,

I want to align several equations in latex.

I want the first and second equations to be in the middle.

The last equation is too long and I want to split it into 2 parts.

I tried

\begin{gather}
Eq1\\
Eq2\\
\begin{multline}
Eq3a\\
Eq3b
\end{multline}
\end{gather}

However, the code cannot be compiled due to multline cannot be used inside other environment. How can I solve the problem?

Thanks for your help very much.

 

[M Quack]

Have you tried eqnarray?

\begin{eqnarray}
a & = & b + c \\
c & = & d + e \\
f & = & a + b + \nonumber \\
  &    &  d + e + f
\end{eqnarray}

[itex]
\begin{eqnarray}
a & = & b + c \\
c & = & d + e \\
f & = & a + b + \nonumber \\
& & d + e + f
\end{eqnarray}
[/itex]

 

[computer2012]

I want the effect of multline, that is, Eq 3a is on the extreme left hand side and Eq 3b is on the extreme right hand side? How can I do that? Thanks.