(x-4y)(x-y)-(x+3y)(x-6y)-5x(2-y),其中x=﹣1/3,y=1/2(x²-nx+3)(x²+3x+m)的展开式中不含x²和x³项,求m和 n的值

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(x-4y)(x-y)-(x+3y)(x-6y)-5x(2-y),其中x=﹣1/3,y=1/2(x²-nx+3)(x²+3x+m)的展开式中不含x²和x³项,求m和 n的值
(x-4y)(x-y)-(x+3y)(x-6y)-5x(2-y),其中x=﹣1/3,y=1/2
(x²-nx+3)(x²+3x+m)的展开式中不含x²和x³项,求m和 n的值

(x-4y)(x-y)-(x+3y)(x-6y)-5x(2-y),其中x=﹣1/3,y=1/2(x²-nx+3)(x²+3x+m)的展开式中不含x²和x³项,求m和 n的值
原式=x²-5xy+4y²-x²+3xy+18y²-10x+5xy
=3xy+22y²-10x
=-1/2+11/2+10/3
=25/3
原式=x⁴+(3-n)x³+(m-3n+3)x²+(9-mn)x+3m
不含则系数为0
所以
3-n=0,m-3n+3=0
所以
n=3
m=3m-3=6