a是方程X^2-3X+1=0的一个根,2a^5-5a^4+2a^3-8a^2+3a=?
a^2-3a+1=0
2a^5-5a^4+2a^3-8a^2+3a
=2a^3(a^2-3a+1)+a^4-8a^2+3a
=a^4-8a^2+3a
=a^2(a^2-3a+1)+3a^3-9a^2+3a
=3a^3-9a^2+3a
=3a(a^2-3a+1)
=0
a是方程X^2-3X+1=0的一个根,2a^5-5a^4+2a^3-8a^2+3a=?
a^2-3a+1=0
2a^5-5a^4+2a^3-8a^2+3a
=2a^3(a^2-3a+1)+a^4-8a^2+3a
=a^4-8a^2+3a
=a^2(a^2-3a+1)+3a^3-9a^2+3a
=3a^3-9a^2+3a
=3a(a^2-3a+1)
=0