平分面上的任意一点到两平面的距离相等设P(x,y,z)则|x-2y+2z+21|/√(1+4+4)=|7x+24z-5|/√(49+576)|x-2y+2z+21|/3=|7x+24z-5|/253|7x+24z-5|=25|x-2y+2z+21|若3(7x+24z-5)=25(x-2y+2z+21)4x-50y-22z+540=02x-25y-11z...