As I said before, except for in math classes, these things don't factor.

So, we have to be prepared to prove this!

Try to factor this guy:

x^2 - 4x + 5

We start with this:

( x     ) ( x     )

Obviously, this is our only option:

( x   1 ) ( x   5 )

Hmm...it sure LOOKS like it will factor...

( x + 1 ) ( x - 5 ) = x^2 - 4x - 5 ... we got the -4, but the -5 is incorrect

Since our possibilities are shot, this thing won't factor.