为什么用x表示未知数
首先使x,y,z表示未知数，用a,b,c表示已的是法国数学卡尔。
他在1637年出版的《方法的附录之一《几何学》中首先引入这种做法。
最初的著作里笛卡尔使用x,y,z的频率相差无几，而很快z的出现频率变少，最后x的使用占据了主流。
笛卡尔在代数学上的成就也使得这种记法广为接受。
由于笛卡尔在引进这些变量名字时并未说明原因，后世的科学史家对此有不同的假设。
一种假设认为x用作未知数是因为阿拉伯文中表示“（尚未知的）东西”是shei，后来在希腊语中转写为xei，首字母为x。
也有人认为是因为物理学中常常用某个物理量的首字母表示之，比如d表示距离，t表示时间，l表示长度等等，而没有x, y, z开头的物理量，所以用来做未知量不会和其它物理量混淆。
还有说法是笛卡尔写作时使用x,y,z的频率其实差别不大，但印刷时考虑到x是最少出现的字母，为了平衡26个字母的使用频率而换成x。
有关x战警 发生时间顺序以及X教授的伤
His words come true Everything has changed This book not worth reading twice Happened I do not know her name Become a good student means to study hard How long do we can realize our dream He asked when we can finish the job Surprising to us that his words and deeds He was determined to study hard His dream is that when scientists His words sound reasonable Hard work necessary to achieve the dream No matter what I do with you This is the best novel I read I want to do is that I can achieve my dream His English is poor because he does not attach importance to reading This is my 3rd Middle School of Education This is our time to study hard Can you show me pictures of it? Professor Lee gave us on how to learn English at a seminar We think he is a good teacher They gave this girl named Chang'e Yesterday, I saw her crying We listen to her sing this song I let him study hard I was walking down the street and suddenly heard someone call my name We are walking in the street and suddenly heard someone shouting for help I'll have to hire someone to repair my bicycle They are old and thin so that the elderly run for two hours I want to go to the tall, pretty girl
x教授读取死侍内心，结果怎样，是在哪个漫画里
死侍拥有传说中的技能“突破次元壁”，简单来说就是死侍知道自己是漫画（电影）角色，教授扫描了他的大脑知道了这些乱七八糟的信息，要么是受刺激死了要么是消息太多脑过载，表现出来的就是脑死亡
15x99十15简单的方式
15x99+15=15x(99+1)=15x100=1500
形容老师讲课好的的成语
共分为AlphaBeta、Delta、Epsilon、Gamma、Omega级，不愿意用简单的音译翻译的原因是这单词分别为希腊语里的第一、、第三、第四、第五个字母和终极的意思，所以就直译了：一、Alpha Level Mutant（一级变种人）人数少于10%，有正常人的外表，有强大的能力并可以随心所欲地控制Astra, Aurora, Avalanche, Banshee, Berzerker, Bishop, Black Tom, Boom Boom, Box (Maddison Jeffries), Cable, Cannonball, Colossus（钢人）, Cordelia Frost, Dazzler, Emma Frost（白皇后）, Erg, Exodus, Firefist, Firestar, Gambit（牌王）, Harry Leland,Healer, Hellion, Husk, Karma, Lady Mastermind, Magik, Magma, Moonstar, Northstar, Plague, Princess Powerful, Professor Charles Xavier（X教授）, Psylocke, Pyro(玩火人), Quicksilver, Rictor, Riptide, Scalphunter, Sebastian Shaw（地狱火俱乐部黑国王）, Selene, Shadowcat（幻影猫）, Shinobi Shaw, Siryn, Sunfire, Tempo, Unuscione, Vanisher, Wallflower, Warpath, Wolfsbane二、Beta level Mutant（二级变种人）占全部变种人的10%，有常人的外表有强大的能力，但无法很好控制Ape, Blindfold, Blowhard, Cyclops（镭射眼）, Daken, Destiny, Havok, Jason Wyngarde, Loa, Madame Web, Mortis, Mystique（魔形女）,Pixie, Random, Rogue（罗刹女）, Skids, Sunder, Surge, The Hunter, Toad, Trevor Fitzroy, Wolverine（金刚狼）, X-23三、Delta Level mutant（三级变种人）占全部变种人的50%以上，是最常见的变种人，有常人的外表，比Alpha级, Beta级甚至Gamma级的能力都弱，但可控Annalee, Beautiful Dreamer, Black Swan, Blindspot, Callisto, Cipher, Cybelle, Domino, Masque, Prodigy, Scrambler, Stinger, Trance四、Epsilon Level Mutant（四级变种人）占全部变种人的20%, 有重大瑕疵，很难生活，能力也不强Bliss, Tar Baby五、Gamma Level mutant（五级变种人）有缺陷，有强大的能力，但有生活障碍Anole, Ariel, Azazel, Beast（野兽）, Black Womb, Bling!, Blob, Caliban, C cont., Cloak and Dagger(?), Dark Beast, Emplate, Feral, Gentle, Graymalkin, Indra, Johnny Dee, Leech, Maggott, Malice, Match, Nightcrawler（夜行者）, Prism, Rockslide, Threnody, Wither六、Omega level mutants（终级变种人）最强大的变种人,可以控制物质、能量，有无强的潜力，近乎不朽Armageddon Man, Darwin（达尔文）, Elixir, Franklin Richards, Goblin Queen, Iceman（冰人）, Jean Grey（琴葛蕾）, Kid Omega, Legion, Magneto（万磁王）, Marvel Girl（惊奇女孩）, Scarlet Witch（红女巫）, Storm（暴风女）, Synch, The Beyonder, Vulcan, Weapon Omega, X-Man
