如何通过电离常数比较ph

怎样解这类不等式题目!① a取何值时,关于X的方程(2/3)X-3a=5(X-a)+1的解是非负数?② 已知不等式X+1 S=(1+1/ 1*2+(2+1/ 2*3)+(3+1/ 3*4)+...+(20+1/ 20*21)S=(1+1/1*2)+(2+1/2*3)+(3+1/3*4)+...+(20+1/20*21)=(1+2+3+...+20)+(1/1*2+1/2*3+1/3*4+...+1/20*21)=(1+2+3+...+20)+[(2-1)/1*2+(3-2)/2*3+(4-3)/3*4+...+(21-20)/20*21]=(1+2+3+...+20)+[(1-1/2)+(1/2-1/3)+(1/3 求值:S=(1+1/1*2)+(2+1/2*3)+(3+1/3*4)+...+(20+1/20*21) （1）求值:S=(1+1×2分之1)+(2+2×3分之1)+(3+3×4分之1)+…+(20+20×21）（2）推广（1）中n个括号相加的情形,的代数式来表示S 给未来的我一封信 动点到两个点A(3,—5),B(2,4)的距离相等,求动点的轨迹方程 As a student,you shouln't break the school r___.We shouldn't spit in p___.He often c___ his students when they make mistakes.We should speak to other people____(有礼貌地).What a ___ (有礼貌的) child He always says “please” and "thank you" yesterday I was ill,so I（） a day（）昨天我生病了所以我休息了一天 关于友谊的二人对话（英文） 直线xcosθ+ycosθ=0的极坐标方程为 求以“Do you agree that we can judge a person by the appearance at the first sight?”为话题的对话英语短对话,2分钟以上 ---How is that,Joan?---Yeah,it's from the boss.She ( ) first whether she likes it.A．shall go B.ought to have gone C.should go D.must have go 请讲详细点选哪个还有为什么不能选CAC应该都可以表“应该”嘛但麻烦讲一下为 英语问题Nobody likes to ___.That's why she was unhappy that day.Nobody likes to ___.That's why she was unhappy that day.A.make fun of B.be laughing at C.PLAY A TRICK ON D.be piayed tricks on xcosα+ysinα-p=0的极坐标方程是什么 英语翻译Baby i'm not here to start a fight But i just thought i'd let you (Just thought i let you know) Cause the way that you've been treating me It so unfair baby its so coldAll i do it put you first I be there any time you want me toMaybe that 英语翻译、 就是keyshia cole 的 fallin out. 一个自然数200820092010,最大的约数是它本身,第四大的约数是多少 抛物线上一点到其焦点的距离等于该点到准线的距离么 英语一分钟对话英语一分钟2人对话,话越短越好,一分钟内说的句数越多越好 为什么抛物线中点到焦点的距离等于点到准线的距离? 二人英语一分钟对话大概初一水平,不要太难的. 谁帮我编个英语一分钟对话英语水平就七年级上册 内容随便 Bubbly歌词翻译【关键是Bubbly在这首歌里的意思是?】 BUBBLY歌词中文翻译 英语翻译V1:I've been awake for a while nowyou've got me feelin like a child nowcause every time i see your bubbly facei get the tinglies in a silly placeC:It starts in my toesand I crinkle my nosewhere ever it goes i always knowthat you make me s playing,are,john,chess,and,Zhang Peng(?)连词成句 John's arms are longer than Zhang Peng's. 新买的电烙铁用了一阵子,头上不平整就用锉刀锉了下,再使用时就很难融化焊锡,而且焊锡粘不上去,怎么办 how __________now?A.do you feel B.is you feeling C.are your feeling D.are you feelingBoth of us are Chinese_______(并列连词)they are Japaneseappendix(阑尾炎）前面用a还是an？ How ＿＿Mike feel?A,is B,are C,do D,does 六年级英语改错题 [How(1)] [is (2)] Mike [feel(3)] how does mike is old语法正确吗