6mx的2次方加4nxy加2x加2xy减x的2次方加y加4不含2次项6mx的2次方加4nxy加2x加2xy减x的2次方加y加4=(6m-1)x²+(4n+2)xy+2x+y+4即6m-1=04n+2=0m=1/6n=-1/2所以6m-2n+2=6×1/6-2×(-1/2)+2=1+1+2=4
