若x.y满足x+=4和x-y=2,求xy分之2x-y+1除以-x分之y+y分之x的值

若x.y满足x+=4和x-y=2,求xy分之2x-y+1除以-x分之y+y分之x的值
若x.y满足x+=4和x-y=2,求xy分之2x-y+1除以-x分之y+y分之x的值

若x.y满足x+=4和x-y=2,求xy分之2x-y+1除以-x分之y+y分之x的值
x+y=4
x-y=2
x=3,y=1
(2x-y+1)/(xy)÷(-y/x+x/y)
=(6-1+1)/3÷[(-1/3)+3]
=2*3/8
=3/4