a平方+a-3=0 a四次+2a三次-a-1=
问题描述：
a平方+a-3=0 a四次+2a三次-a-1=
tell me please 3q
答
a^2+a-3=0
a^2+a=3
a^4+2a^3-a-1
=a^2*(a^2+a)+a^3-a-1
=a^3+3a^2-a-1
=a*(a^2+a)+2a^2-a-1
=2a^2+2a-1
=2(a^2+a)-1
=5