. . . . .[tex]x^2 \, - \, y^2 \, = \, (x \, - \, y)(x \, + \, y)[/tex]
...will display as:
. . . . .
(Note: The " \, " code in the "[tex]" line above inserts spacing, which can be very helpful for readability.)
A quick-start guide is planned to be posted later.
