谢.

这个很简单啊,A+B的行向量组能被A的秩和B的秩表示出来,因此就有这道题的结论.

我受够了从事毫无前途的工作.
我理解你的问题,但我不确定应该给你些什么建议.

sinA=(3-m)/(m+5)
cosA=(2m-4)/(m+5)
m*m-6m+9+4m*m-16m+16=m*m+10m+25
m=8

c

sin[α+(k+1)л]+sin[α-(k+1)л]/sin(α+kл)*cos(α-kл)
k偶数
=[sin[α+л]+sin[α-л] ]/sinα*cosα
=2sin(α+л)/(sinacosa)=2sin(-a)/(sinacosa)=-2/cosa
k奇数
=[sinα+sinα]/sin(α+л)*cos(α-л)
=2sina/[sin(-a)*cos(л-α)]
=2/cosa

Dear John,
How is going recently? Due to some unpleasant experience in work, I really want to share with you.
Mary has promoted me to trainee supervisor for half a year.on one hand, my payment hasn't changed, on the other hand, my workload has increased a lot.
Ann, who is my manager, possesses a very bad impression on me. she always evaluate me with low working efficiency, thus forces me to overwork almost everyday! Till now, I didn't even pass the Middle EV. God knows when would she promote me to the formal supervisor.
I am now in a paradox and confused. John ,can you kindly do me a favor with some advice?
Yours faithfully,
Sam.

Green

two
They bought some clothes in the shop.
two
no
no

72x-81=x-1

（a+2）∧2+√b-3=0
a+2=0
a=-2
b-3=0
b=3
a^b
=(-2)^3
=-8
如还有新的问题,请不要追问的形式发送,另外发问题并向我求助或在追问处发送问题链接地址,

11,BC=1
13,3秒
给我啦
没办法
只能两边平方啦
于是就是
【√（R²-4²）+1】²=【√（R²-3²）】²
（R²-4²）+2√（R²-4²）+1=（R²-3²）
整理一下就是
√（R²-4²）=3
再两边平方就是
（R²-4²）=9
于是
R²=25
还要R>0吧
于是
R=5

水管

2

3．3ab-4ab+8ab-7ab+ab=______．
4．7x-(5x-5y)-y=______．
5．23a3bc2-15ab2c+8abc-24a3bc2-8abc=______．
6．-7x2+6x+13x2-4x-5x2=______．
7．2y+(-2y+5)-(3y+2)＝______．
11．(2x2-3xy+4y2)+(x2+2xy-3y2)=______．
12．2a-(3a-2b+2)+(3a-4b-1)=______．
13．-6x2-7x2+15x2-2x2＝______．
14．2x-(x+3y)-(-x-y)-(x-y)＝______．
16．2x+2y-[3x-2(x-y)]=______．
17．5-(1-x)-1-(x-1)=______．
18．( )+(4xy+7x2-y2)=10x2-xy．
19．(4xy2-2x2y)-( )=x3-2x2y+4xy2+y3．
21．已知A=x3-2x2+x-4,B=2x3-5x+3,计算A+B=______．
22．已知A=x3-2x2+x-4,B=2x3-5x+3,计算A-B=______．
23．若a=-0.2,b=0.5,代数式-(|a2b|-|ab2|)的值为______．
25．一个多项式减去3m4-m3-2m+5得-2m4-3m3-2m2-1,那么这个多项式等于______．
26．-(2x2-y2)-[2y2-(x2+2xy)]=______．
27．若-3a3b2与5ax-1by+2是同类项,则x=______,y=______．
28．(-y+6+3y4-y3)-(2y2-3y3+y4-7)＝______．
29．化简代数式4x2-[7x2-5x-3(1-2x+x2)]的结果是______．
30．2a-b2+c-d3=2a+( )-d3=2a-d3-( )=c-( )．
31．3a-(2a-3b)+3(a-2b)-b=______．
32．化简代数式x-[y-2x-(x+y)]等于______．
33．[5a2+( )a-7]+[( )a2-4a+( )]=a2+2a+1．
34．3x-[y-(2x+y)]=______．
35．化简|1-x+y|-|x-y|(其中x＜0,y＞0)等于______．
36．已知x≤y,x+y-|x-y|=______．
37．已知x＜0,y＜0,化简|x+y|-|5-x-y|=______．
38．4a2n-an-(3an-2a2n)＝______．
39．若一个多项式加上-3x2y+2x2-3xy-4得
2x2y+3xy2-x2+2xy,
则这个多项式为______．
40．-5xm-xm-(-7xm)+(-3xm)=______．
41．当a=-1,b=-2时,
[a-(b-c)]-[-b-(-c-a)]＝______．
43．当a=-1,b=1,c=-1时,
-[b-2(-5a)]-(-3b+5c)＝______．
44．-2(3x+z)-(-6x)+(-5y+3z)=______．
45．-5an-an+1-(-7an+1)+(-3an)＝______．
46．3a-(2a-4b-6c)+3(-2c+2b)=______．
48．9a2+[7a2-2a-(-a2+3a)]=______．
50．当2y-x=5时,5(x-2y)2-3(-x+2y)-100=______．

生生不息,一切生存都在更替.花儿要是不凋落,总占据枝头,新的蓓蕾就没有生长的地方了

做个好梦,睡得好,不会说我不想
have a good night [简明英汉词典]
睡得好

先证明三角形ABE≌三角形DFA（AAS）,所以AF＝BE,所以AE－AF＝BC－BE,所以CE＝BF

意思就是明天就爱那个是暂新的一天
我觉得多用于安慰语境
明天要来了,今天的一切不美好都将过去
崭新的一天在等待着

the c____ in this book is funny
content这本书的内容很有趣

24

两式相减
2y+y=a-3-3
3y=a-6
y=1/3a-2
x=y+3=1/3a-2+3=1/3a+1
1/3a+1

1.错,4/(100+4)≠4%
2.错,2+1=3
3.错,应该是正比例
4.对
5.对

make out of
Wiki
由...制成,用...做原料
He made out of the cabin at once on hearing the siren.
他一听到汽笛声就立即走出船舱.
Many things are made out of bamboo.
很多东西是由竹子做出的.

试译如下：
如果被估税的商品或者说相同或与之同类的商品在和它们输入到俄联邦关税区时候的状态一样的情况下在俄罗斯联邦销售,那么做为商品的关税定价的基础就是商品的单价,该单价来自于被估税的商品或者说相同或与之同类的商品数量最集中的地方向和俄联邦内的销售人毫无关系的人们销售的单价,销售时间是被估税的商品输入到俄联邦关税区的或与之相符合的期限之内.

It's too good to be true!的翻译是：
好得难以置信.

所谓整除只能用在整数之间,因为3.6和0.9都不是整数,所以即使得到的是整数,也不能说是整除.也就是说非整数之间的除法,不存在整除这个概念.你这个问题本身就存在错误.

well done 做的好
good job 好的作
good for you
一般对应三层意思：
1.Congratulations 祝贺你!
2.Happy/Glad to hear that 真为你高兴.
3.You deserve it 这是你应得的.
对于你说的情况,该选以上哪一种,你自己懂的（其实三种都差不多）
补充一点,good for you 还有2层比较负面的意思：
1.对对方的发言表示反讽
2.对对方的发言表示敷衍

-24x^7y^3

ACBCABD

可能指[俚]姑娘; 女子
你马子是我的了

3
1 2 3 4 5 7 9

√4825+5/2

101+102+103+……+198+199
=99*(100)+(1+2+3+4+5+……+98+99)
=9900+(1+99)*99/2
=14850

∠BDA′=2∠A

平方差
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)……(1-1/20)(1+1/20)
=(1/2)(3/2)(2/3)(4/3)……(19/20)(21/20)
中间约分
=(1/2)(21/20)
=21/40

1. By the time we arrived the meeting was over.
我们到达时,会议已结束了.
2. By the time he is ten, he has outgrown his older brother.
他十岁的时候就已经长得比他哥哥高了.
3. The injured man was fairly far gone by the time the ambulance arrived.
救护车到时那伤者已生命垂危.
4. By the time the bus came so many people were waiting that it was a free fight to get on it.
公共汽车来的时候,等车的人很多,成了一场挤车的混战.
5. I shall be pushing up daisies by the time the project is finished.
等到这项目完成时, 我早已入土了.
6. I corrected my watch by the time signal.
我按报时信号校正我的表.
7.by the time i want to school,it already had in class
当我到学校时,已经开始上课了!~

证明：过点P作PE⊥AD于E,延长EP交BC于F
∵PE⊥AD
∴PA²-AE²＝PE²,PD²-DE²＝PE²
∴PA²-AE²＝PD²-DE² 1）
∵AD∥BC,PE⊥AD
∴PF⊥BC
∴PB²-BF²＝PF²,PC²-CF²＝PF²
∴PB²-BF²＝PC²-CF² 2）
∵矩形ABCD,PE⊥AD,PF⊥BC
∴矩形ABFE,矩形CDEF
∴AE＝BF,DE＝CF
∴1）-2）得
PA²-PB²＝PD²-PC²
∴PA²+PC²＝PB²+PD²

既然一个工作值得做它就值得做好.这里的at all是假设、既然、即使 的意思,用于肯定句有时候at all也有竟然的意思

书香校园

第一题：D 爸爸和妈妈在婚礼后就开始积攒家庭图书馆的书.
第二题：D 我们的课总是从开场白开始.
第三题：C Кузьмин 很快对他的病态自尊感到厌烦.
第四题：B 他由于成绩太差而被取消了奖学金.

孙之翰 says:庆历中 appionted 杜衍,范仲淹 and 韩琦 as political minister,and appionted 欧阳修,蔡襄及甫 and others as manager who find
fault of him ,

1.- Алло, это база? - Нет, вы не туда попали. Это ракетная база.2.Вы уже проехали! пересадку лучше сделать на следу...

Trust
Can people trust each other?
I think we can trust each other in our country.
Firstly,as is known to all,our country is devoted to build a harmonious society.What is harmonious society?For us,it’s a world full of honest,friendly atmosphere,justice,fair and open competition between social members,regions and departments.Imagine that everybody of us won’t trust each other any more,how can the beautiful “harmonious society” come true?
You may say that here are so many problems and contradictions around us.Everyone seems to look at others with suspicion.Every home there must be with an anti-theft door to keep safe.Some new bicycles are locked with two locks,but even that cannot prevent them from being stolen.But do you know that it is a normal phenomenon in every country,even the most developed USA?To protect your own possession is one of your daily task,not others’.
Secondly,mutual trust is also essential for making a real friend.A slight smile when we meet each other will shorten our distance.Loyalty is the basic foundation for people to trust and communicate with each other,thus,keep the society in harmony.Admittedly,relationships are established on mutual trust and loyalty which cannot be easily altered to maintain genuine relationships.
Of course,it is a fact that deceiving is a threat to the stability of our society.Deceivers damage the principals of social “games”.More over,they destroy the backbone-trust,which our society depends on.But it is a fact that you can only avoid or keep away from rather than put an end to.In that situation,why do we sigh there instead of confronting it?
What shall we do to end up the unexpected atmosphere?Firstly we should be honest,and treat other people with an open mind.Secondly,for the poor,we should give them a hand for help.The most important is to help those children who can’t afford to go to school,because they are the hope for the poor families and the poor regions.Thirdly,for our individuals,when handling some business,we should accord to the principle.And when we have the accurate evidence of bribing,we may report to the authorities and make them exposed to the public.If each of us can do so,contradiction in our society can be reduced and the harmonious society can come true earlie
Believe
Believe in your dreams.
Believe in today.
Believe that you are loved.
Believe that you make a difference.
Believe we can build a better world.
Believe when others might not.
Believe there’s light at the end of the tunnel.
Believe that you may be that light for someone else.
Believe that the best is yet to be.
Believe in yourself.
I believe in you.
二选一吧,

i asked sir not to tell anybody
否定在to前
第二句句义变了：我问：先生没有告诉任何人

1.find sb.doing sth.
2.你说得对

m分之1

我什么都会
只是懒得动而已