已知（3x^2-2x+1)(x+m)的乘积中不含x^2项,求m的值

1.3x^2-2x+1)(x+m)
=3x^3+(3m-2)x^2+(1-2m)x+m
3m-2=0
m=2/3
2.3a^(n+1)-6a^n+3a^(n-1)
=3a^(n-1)*a^2-6a^(n-1)*a+3a^(n-1)
=3a^(n-1)(a^2-2a+1)
=3a^(n-1)(a-1)^2
3.1.345×0.345×2.69-1.345^3-1.345×0.345^2
=1.345(0.345*2.69-1.345^2-0.345^2)
=-1.345(1.345-0.345)^2
=-1.345

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