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已知a2+4a+1=0,且
a4+ma2+1
3a3+ma2+3a
=5
,则m=______.
人气:353 ℃ 时间:2020-03-27 04:33:55
解答
∵a2+4a+1=0,∴a2=-4a-1,
a4+ma2+1
3a3+ma2+3a
=
(−4a−1)2+ma2+1
3a(−4a−1)+ma2+3a

=
(16+m)a2+8a+2
(m−12)a2

=
(16+m)a2+8a+2
(m−12)(−4a−1)

=
(16+m)(−4a−1)+8a+2
(m−12)(−4a−1)
=5,
∴(16+m)(-4a-1)+8a+2=5(m-12)(-4a-1),
原式可化为(16+m)(-4a-1)-5(m-12)(-4a-1)=-8a-2,
即[(16+m)-5(m-12)](-4a-1)=-8a-2,
∵a≠0,
∴(16+m)-5(m-12)=2,
解得m=
37
2

故答案为
37
2
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