已知
|
答案:
∵
∴a=
a4+7a3+13a2+5a+1 =a4+4a3+4a2+2a3+8a2+8a+a3+2a2+a-a2-4a-4+5 =a2(a+2)2+2a(a+2)2+a(a+1)2-(a+2)2+5 =a(a+2)3+a(a+1)2-(a+2)2+5 =a×(
=25-10
=3. 故选:D. |

已知
|
答案:
∵
∴a=
a4+7a3+13a2+5a+1 =a4+4a3+4a2+2a3+8a2+8a+a3+2a2+a-a2-4a-4+5 =a2(a+2)2+2a(a+2)2+a(a+1)2-(a+2)2+5 =a(a+2)3+a(a+1)2-(a+2)2+5 =a×(
=25-10
=3. 故选:D. |