Help, I don't know how to factor, evidently!

[Guest]

So.

lim x --> 1, of x^3 - 1
---------
x^2 - 1 .

The bottom factors nicely into (x + 1) and (x - 1).

But what to do with the top, so I can plug in the one and just go with it? I need to be able to pull out either an (x + 1) or (x - 1), but how do I get there?

 

[royhaas]

You should know from algebra, or simply perform the division, that \(\displaystyle x^3-1=(x-1)(x^2+x+1)\).