已知:a^2 +a=1/3.求6a^4 +15a^3 +10a^2 的值如题没有抄漏啊,题目是这样的饿

已知:a^2 +a=1/3.求6a^4 +15a^3 +10a^2 的值
如题
没有抄漏啊,题目是这样的饿

6a^4 +15a^3 +10a^2
=6a^4+6a^3+9a^3+9a^2+a^2
=6a^2(a^2+a)+9a(a^2+a)+a^2
=6a^2*(1/3)+9a(1/3)+a^2
=3a^2+3a
=3(a^2+a)
=3*(1/3)
=1

a^2 +a=1/3,
a^2+a-1/3=0,
6a^4 +15a^3 +10a^2
=6a^2(a^2+5a/2+5/3)
=6a^2[(a^2+a-1/3)+3a/2+2]
=6a^2*0+9a^2+12a,
题目有抄漏吧?

a^2 +a=1/3
6a^4 +15a^3 +10a^2=
a^2(6a^2+6a+9a+10)=
a^2(6(a^2+a)+9a+10)=
a^2(6(1/3)+9a+10)=
a^2(12+9a)=
a^2(9a+9+3)=
a(9(a^2+a)+3a)=
a(9(1/3)+3a)=
a(3+3a)=3a+3a^2=1