| 2a3(a2+1)-a2(5a2+8) |
| a2+1 |
=
| 2a3(3a-1 +1)-a2[5(3a-1)+8] |
| a2+1 |
=
| 2a3•3a-a2[15a+3] |
| a2+1 |
=
| 6(3a-1)2-(3a-1)[15a+3] |
| a2+1 |
=
| (3a-1)[6(3a-1)-(15a+3)] |
| a2+1 |
=
| (3a-1)(3a-9) |
| a2+1 |
=
| 9(3a-1)-30a+9 |
| 3a |
=
| -3a |
| 3a |
=-1．
故答案为：-1．
| 2a5-5a4+2a3-8a 2 |
| a2+1 |
| 2a3(a2+1)-a2(5a2+8) |
| a2+1 |
| 2a3(3a-1 +1)-a2[5(3a-1)+8] |
| a2+1 |
| 2a3•3a-a2[15a+3] |
| a2+1 |
| 6(3a-1)2-(3a-1)[15a+3] |
| a2+1 |
| (3a-1)[6(3a-1)-(15a+3)] |
| a2+1 |
| (3a-1)(3a-9) |
| a2+1 |
| 9(3a-1)-30a+9 |
| 3a |
| -3a |
| 3a |