Attempt at proving result from intro to pure mathematics by liebeck

Looks valid to me. And when you wanna do some more latex on a new line you should end the first line (/latex) and start a new (latex)(/latex) on the next line.
$n=(x+1)^3-(x+1)$
$n = x(x+1)(x+2)$

It is valid but you don't really need the substitution:

$m^3-m = m(m^2-1) = (m-1)(m)(m+1)$

This is also the product of three consecutive integers.

Looks valid to me. And when you wanna do some more latex on a new line you should end the first line (/latex) and start a new (latex)(/latex) on the next line.

Other things being equal, it's better to use separate [noparse]$...$[/noparse] blocks, because then each line is treated separately by the vBulletin system. It makes it easier for other people to put comments between lines etc.

I will bear that in mind in the future, cheers How come the n and x'es changed in the second line of my reply? Never seen that happen before.

I will bear that in mind in the future, cheers How come the n and x'es changed in the second line of my reply? Never seen that happen before.

Or use these like this \\ sometimes it required \\ \\ to look neat but today it is just one set weird n and x on second line, what's going on?

$n=(x+1)^3-(x+1) \\ [br]n = x(x+1)(x+2)$

I'd suggest writing "\displaystyle" on each spaced line. That should do the trick.

$[br][br]\displaystyle n=(x+1)^3-(x+1)[br][br]\displaystyle n = x(x+1)(x+2)$

I'm no expert mind.

$n=(x+1)^3-(x+1) \\ n = x(x+1)(x+2)$

See my LaTex.

To start a new line, just write "\\" but then don't press the enter key, write everything in the same line.

NB: I might be wrong because i am not an expert at it.