Question

Номер 684, под буквой "в"

Answer 1

a³-a²-a+1=(a-1)²(a+1)
a³-a²-a+1=(a²-2a+1)(a+1)
a³-a²-a+1=a³+a²-2a²-2a+a+1
a³-a²-a+1=a³-a²-a+1
a³-a³-a²+a²-a+a=1-1
0=0