The product (a+b) (a-b) (a²-ab+b²) (a²+ab+b²) is equal to

17

(a-b)³+(b-c)³+ (c-a)³=

18

=

20

If = -1, then a³-b³ =

21

The product (x²-1) (x⁴+x²+1) is equal to=