In my book there is a following example:

Prove by induction that 3 is a factor of

the example has one step which baffles(in addition to the fact that I´m already baffled by induction as it is)

(why do you first subtract 1 and then add 1? Is this the mathematician´s creativity?)

(what happens here?)

I´m a bit worried about this induction thing, because I´ve been trying to solve the homework problems for three days with very little progress. If anyone could help me with this problem I would be really grateful.

One more thing, does anyone know any good book which would have mathematical induction for dummies?

All help is appreciated very much.