已知A=2x^2+3ax-2x-1 B=-x+ax-1 且3A+6B的值与x无关,求-5a+2012
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已知A=2x^2+3ax-2x-1 B=-x+ax-1 且3A+6B的值与x无关,求-5a+2012
已知A=2x^2+3ax-2x-1 B=-x+ax-1 且3A+6B的值与x无关,求-5a+2012
已知A=2x^2+3ax-2x-1 B=-x+ax-1 且3A+6B的值与x无关,求-5a+2012
3A+6B
=3(2x²+3ax-2x-1)+6(-x²+ax-1)
=6x²+9ax-6x-3-6x²+6ax-6
=(15a-6)x-9
值与x无关
则x系数为0
15a-6=0
a=2/5
所以-5a+2012
=-2+2012
=2010