沈阳铁路实验小学

已知实数x,y满足-4≤x-y≤-1,-1≤4x-y≤5,则9x-y的取值范围是（）答案是[-1,20],但我举例：若x∈[1,2],y∈[3,5],则也符合题目条件,但这样算出来的取值范围是[4,15],这是为什么呢?高一刚学不等式 蓝色香水鱼是啥意思啊 已知实数x,y满足-4≤x-y≤-1,-1≤4x-y≤5,则z=9x-y的取值范围为( )为什么不能直接解出x,y的取值范围,然后再求9x-y的范围? 已知实数x,y满足-4≤x-y≤-1,-1≤4x-y≤5,则9x-y的取值范围是（） 已知实数x,y满足-4≤x-y≤-1,-1≤4x-y≤5,则9x-y的取值范围是（） 答案是[-1,20] 但我根据答案所给方法求得的是 [4,15],这是为什么呢? Which is the better还是which is better Which is better?CPU酷睿四核 i5 760 主板七彩虹C.H55T V21内存威刚2G DDR3 1333硬盘西数/日立500G 7200显卡七彩虹430灵动鲨 D3 真实1G/铭瑄GT430巨无霸真实1G机箱航嘉百盛时尚机箱电源九鼎450W电源CPUAMD AM3六 A or B,which is better还是A and B,which is better? Which is I like better? 560 650ti which is better? 上面一个云下面一个亏是什么字 there is an earthquake happening in Yushu还是there is an earthquake happened in Yushu? It ----now.There is a lot of ----in this season.So it is always ---here 下雨 Earthquake bring casualties and losses.In fact,there are usually many signs b an earthquake reallyEarthquake bring casualties and losses.In fact,there are usually many signs b—— an earthquake really h—— 查去掉一笔是什么字 "better and better"咋翻译? 英语翻译 You had better not stand there .翻译,还有为什么动词用原形?是因为not 吗? 英语翻译 movie:comedies,action movies,documentaries……还有哪些电影?（用英语表达出） 英语翻译1 这家公司已经成立10年了.英语翻译是?（注意时态 和动词的 准确性,has been established for 10 years.记得好像不行,短暂动词,不能跟 For 一段时间一起用）2 这个公园建成 多少年了?/ 建成 大学新生生活感悟5000字实在写不出来了. 是cause damage to doing sth还是 cause damage to do sth? What damage could a earthquake cause?（in English please） do cause damage to doing还是do cause damage to do有什么很经典的句子么,有什么典型用法么. Action movies 英语音标怎么读?要标准的.看音标怎么读单词? 上面有个日,下面有个云是什么字? 那是我们第一次相遇的日子 一次不到45秒的邂逅 用英文怎么说 the less likely it is that the corrosion rate is greater than anticipated.it is that是什么后面的anticipated省略了corrosion rate吧 有没有 it is likely （FOR SB) to do 我知道到有 It is likely that / SB IS LIKELY TO DO应该没有 IT IS PROBABLE TO DO 我只知道IT IS PROBABLE THAT action film和action movie 有什么区别吗 you'd better后面接动词什么形式