若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于( )若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于( )
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![若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于( )若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于( )](/uploads/image/z/1612192-40-2.jpg?t=%E8%8B%A5%E5%A4%9A%E9%A1%B9%E5%BC%8F2%EF%BC%88x%26%23178%3B-3xy-y%26%23178%3B%EF%BC%89-%EF%BC%88x%26%23178%3B-3mxy%2B2y%26%23178%3B%EF%BC%89%E4%B8%AD%E4%B8%8D%E5%90%ABxy%E9%A1%B9%2C%E5%88%99m%E7%AD%89%E4%BA%8E%EF%BC%88+%EF%BC%89%E8%8B%A5%E5%A4%9A%E9%A1%B9%E5%BC%8F2%EF%BC%88x%26%23178%3B-3xy-y%26%23178%3B%EF%BC%89-%EF%BC%88x%26%23178%3B-3mxy%2B2y%26%23178%3B%EF%BC%89%E4%B8%AD%E4%B8%8D%E5%90%ABxy%E9%A1%B9%2C%E5%88%99m%E7%AD%89%E4%BA%8E%EF%BC%88+%EF%BC%89)
若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于( )若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于( )
若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于( )
若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于( )
若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于( )若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于( )
多项式2(x²-3xy-y²)-(x²-3mxy+2y²)
=2x²-6xy-2y²-x²+3mxy-2y²
=x²+(3m-6)xy-4y²
∵不含xy项
∴3m-6=0
∴m=2
原式=2x²-6xy-2y²-x²+3mxy-2y²
=x²+(3m-6)xy-4y²
不含则系数为0
3m-6=0
m=2
若多项式2(x²-3xy-y²)-(x²-3mxy+2y²)中不含xy项,则m等于(2 )