6x²+mxy-3y²+3x+10y-3
=6x²+(my+3)x-(3y²-10y+3)
=6x²+(my+3)x+(3y-1)(3-y)
按“双十字相乘法”
若能“凑”成中间项,必须是
原式=[x-(3y-1)][6x-(3-y)]=6x²+(3-17y)x+(3y-1)(3-y) 或
原式=[2x+(3y-1)][3x+(3-y)]=6x²+(3+7y)x+(3y-1)(3-y)
对比,可知
3-17y=3+my.====>m=-17
3+7y=3+my,===>m=7
∴m=7或m=-17