x-3y=-2得x=3y-2（x+2+y+4）×（x+2-y-4）=x²-y²（x+y+6）×（x-y-2）=x²-y²x²-xy-2x+xy-y²-2y+6x-6y-12=x²-y²x²-y²-4x-8y=x²-y²-4x-8y=0带入x=3y-2-4...