问题
填空题
若a2-3a+1=0,则3a3-8a2+a+
|
答案
∵a2-3a+1=0,
∴a2=3a-1,a2+1=3a,
∴3a3-8a2+a+
3 |
a2+1 |
=3a3-8a2+a+
3 |
3a |
=3a3-8a2+a+
1 |
a |
=3a3-8a2+a+
3a-a 2 |
a |
=3a3-8a2+3,
=3a(3a-1)-8a2+3,
=a2-3a+1+2,
=0+2,
=2.
若a2-3a+1=0,则3a3-8a2+a+
|
∵a2-3a+1=0,
∴a2=3a-1,a2+1=3a,
∴3a3-8a2+a+
3 |
a2+1 |
=3a3-8a2+a+
3 |
3a |
=3a3-8a2+a+
1 |
a |
=3a3-8a2+a+
3a-a 2 |
a |
=3a3-8a2+3,
=3a(3a-1)-8a2+3,
=a2-3a+1+2,
=0+2,
=2.