已知x﹥0，y﹥0，x*x+y*y-xy=1，求x*x-y*y的最大值、最小值

what's the 我国民族主义核心是什么党课的内容啊.貌似是爱国主义 what's the time是什么中文意思 Tell'm that's not' u,coz I...miβ u what's the time It's_________.A.a quarter past fiveB.five past a quarter C.forty past five D.forty to five is it form your homr to the post office fifteen minutes by bus-______is it form your homr to the post office -fifteen minutes by busA.How farB.How long 15.What’s the time? The office was filled with smoke.可以把with改成by吗? By the time she was fifteen,Kitty ( )(teach)herself a foreign language,是has taught 还是had啊? what's wrong with lucy?__ got a fever. 2012到底怎么回事啊? 我既然是人类.这个是怎么回事 2012到底是怎么回事?有科学根据吗?可不可以把依据告诉我? 人类到底怎么了?现在的人类到底怎么了,难道说人们不知道欲望将把我们反噬,是不是要到某天真的像生化危机那样 把人类自己毁掉才可以,问什么人类越发展思考的越少?人类怎么了?难道要高 人类这种情况是怎么回事啊比如说跑步 明明没劲了.却还能跑很长时间 到最后感觉要到了极限了.靠意志力往下撑了..不是没劲了么..还能跑..潜能的激发 这个貌似很牛逼啊..（据说一个男的把 Glossy eight by ten似乎是说照片的,这个eight by ten是尺寸么?单位是什么?谢谢楼下的说明，但是还有eight by ten,glossy的说法，我觉得这两项应该是分开的……照片可以说光滑，但这个eight by ten我猜 eight-to-ten-minute 什么意思嘛是讲一段视频时提到的这些单词 了解孔子的哪些事情 旧民族主义向新民族主义转变的必要性是 高中历史 宗教改革里的民族主义 和 宗教民族主义是什么意思?拜托解释一下吧 I tasted some oranges on the farm（改为一般疑问句）———— ———— ———— ———— oranges on the farm 1.They tasted oranges on the farm(该否定句） They （） （） oranges on the farm.2.He did his homework yesterday evening(改否定句）He () () his homework yesterday evening.3.He would like to play basketball(改同义句）He () () play ba 1.they tasted oranges on the farm (改为否定句）2.he did his homework yesterday day evening（改为否定句 ）3.he would like to play basketball（改为同义句）4.this is her comb（改为同义句）5.this skateboard is from my friend（ Su Hai tasted apples on the farm last Tuesday .改为否定句,一般疑问句,肯定回答 划线提问tasted apples 为什么要生存哦烦死了, please show your passport to the man变否定句 蜡烛灯上市英文名字新品牌上市蜡烛水晶灯跪求英文名称.老板要几个 Daniel.you aren't ____what I'm saying what are you doing A.hearing B.listening to 我选的是A,是错误的.为什么错?答案B为什么是对的?翻译这句话 寓言故事比较短的 What are you (）?the weather report.A.listening B,hearing C.listening to理由 —What are you _____ —Some important news.A.hearing B.hearing to C.listening D.listening to --what are you_______?---The nice music.It sounds sweet.A.listening to B.listening C.hearing to D--what are you_______?---The nice music.It sounds sweet.A.listening to B.listening C.hearing to D.hearing