若xy=负根号2,x-y=5根号2 -1,则(x+1)(y-1)=?(要详细过程,加悬赏

2024-11-18 12:16:23
推荐回答(1个)
回答(1):

(x+1)(y-1)
=xy-x+y-1
=xy-(x-y)-1
=(-√2)-(5√2-1)-1
=-6√2