\[...\] is used to typeset a single equation, not multiple equations.
You need to use an environment that allows for multiple equations. One way is to use
gather, but I normally use
align, both from the
- With display math environments if you leave blank lines in between you get additional vertical spacing and the possibility of a page break between a paragraph and following display.
- If you don't want the equations numbered use the starred versions of the environments:
- A really good reference is Herbert Voss's comprehensive review of mathematics in (La)TeX.
a + b = c \\
a = c - b
With the align environment you can align equations:
a + b &= c \\
a &= c - b