a³+3a²+3a+2等于几

a³+3a²+3a+2等于几
a³+3a²+3a+2等于几

a³+3a²+3a+2等于几
原式=a³+2a²+a²+2a+a+2
=（a+2）a²+（a+2）a+（a+2）
=（a+2）(a²+a+1)

原式=a³+2a²+a+a²+2a+1+1=a(a+1)²+(a+1)²+1=(a+1)(a+1)²+1=(a+1)³+1

是因式分解吧？
a³+3a²+3a+2＝﹙a³+3a²+3a+1﹚+1＝﹙a+1﹚³+1＝[﹙a+1﹚+1][﹙a+1﹚²-﹙a+1﹚+1]
＝﹙a+2﹚﹙a²+a+1﹚