已知-x（3x^2-ax+1）+3x^3-2x^2中不含x式的二次项,则a=_____.

已知-x（3x^2-ax+1）+3x^3-2x^2中不含x式的二次项,则a=_____.
已知-x（3x^2-ax+1）+3x^3-2x^2中不含x式的二次项,则a=_____.

已知-x（3x^2-ax+1）+3x^3-2x^2中不含x式的二次项,则a=_____.
化简得（a-2)x^2-x
而二次项系数为零
所以a-2=0
即a=2

a=2

2

（-x）*（-ax）-2x^2=0
a=2

-3x^3+ax^2+3x^3-2x^2
ax^2=-2x^2
a=2