a^2+3a+1=0
所以a^2+3a=-1
a^2+3a+1=0
所以a^2+1=-3a
两边除a
a+1/a=-3
a^4+3a^3-a^2-5a+(1/a)-2
=a^2(a^2+3a)-a^2-6a+a+1/a-2
=-1*a^2-a^2-6a+(-3)-2
=-2a^2-6a-3-2
=-2(a^2+3a)-5
=-2*(-1)-5
=-3
a^2+3a+1=0
所以a^2+3a=-1
a^2+3a+1=0
所以a^2+1=-3a
两边除a
a+1/a=-3
a^4+3a^3-a^2-5a+(1/a)-2
=a^2(a^2+3a)-a^2-6a+a+1/a-2
=-1*a^2-a^2-6a+(-3)-2
=-2a^2-6a-3-2
=-2(a^2+3a)-5
=-2*(-1)-5
=-3