(x-y-6)a=y-2x+4则x-y-6=y-2x+4=0时成立所以x=-2，y=-8所以直线过A(-2,-8)所以最大距离就是AP=1041314631
应该是x(y-1)-y(x-1)=4xy-x-xy+y=4-x+y=4x-y=-4原式=(x²-2xy+y²)/2=(x-y)²/2=16/2=8
