Can you multiply this polynomial?

bcarvings
Mon, 06 Jul 2009 20:19:58 +0000

The book says the answer should be t^24-4t^18+6t^12-4t^6+1

Also I don’t understand how (x-1)(x+1)(x-1)(x+1)…
equals (x^2-1)^4.

Please help…