求方程:0= -x平方-2x+3

求方程:0= -x平方-2x+3


(x+3)(x-1)=0
x1=-3,x2=1



已知a是已知數,當a取什麼值時,方程a的平方x的平方-x的平方+2x-2ax-3=0是關於x的一元一次方程





已知a.b屬於R,函數f(x)=ax^2+bx+1的值域為[0,+&]且f(-1)=0
(1)求a.b的值(2)若函數g(x)=f(x)-kx,x屬於[-2,2]是單調函數,求實數k的取值範圍.


1、
f(-1)=a-b+1=0
b=a+1
所以f(x)=ax²;+(a+1)x+1
=a[x+(a+1)/2a]²;+1-(a+1)²;/4a
最小值=0
所以1-(a+1)²;/4a=0
a²;-2a+1=0
(a-1)²;=0
a=1,b=a+1=2
2、
f(x)=x²;+2x+1
g(x)=x²;+(2-k)x+1
x屬於[-2,2]是單調函數
所以對稱軸x=-(2-k)/2不在這個區間
所以-(2-k)/22
所以k6



一個梯子下底比上帝多2cm,高是5cm,面積是40平方釐米,求上低.我求的上低是17.5cm代入了是錯的啊…
我算式是:9x+X+2)*5/2=40 2X+5=40 2X=35 X=35/2 X=17.5


設上底為X,則下底為X+2
列公式:
[X+(X+2)]*5*(1/2)=40
(2X+2)*5=80
2X+2=16
X=7
1/2是乘以0.5或除以2,你自己會寫就行了.
答:上底等於7
往回帶完全正確.
現在在上大學的大姐姐,



數列1/5,3/5,1,7/5……的第11項a11=


21/5



a的10次方加b的8次方等於


10a加8b



初一數學實際問題與一元一次方程(行程問題)一架飛機於兩城之間,一次單程飛行順風是需要5小時30分,逆風時需要6小時.已知風速每小時24千米,求兩城之間的距離


設飛機無風情况下速度為x千米/小時:
(x+24)*5.5=(x-24)*6
(6-5)x=(6+5.5)*24
x=276千米/小時
兩城之間距離:(x-24)*6=(276-24)*6=252*6=1512千米



一列數1,1,2,3,5,8,13,21…從第三項開始每一項是前兩項的和,此數列的第2000項除以8的餘數是多少?


因為此數列除以8的餘數的規律是:1,1,2,3,5,0,5,5,2,7,1,0,1,1,2,3,…它的迴圈週期是:1,1,2,3,5,0,5,5,2,7,1,0;2000÷12=166…8,在迴圈數中第8個數對應的是5,囙此第2000項除以8的餘數是5;答:此數列的第2000項除以8的餘數是5.



不等式(x-3)(x+2)≥0的解集是______.


不等式(x-3)(x+2)≥0,可化為x−3≥0x+2≥0或x−3≤0x+2≤0,解得:x≤-2或x≥3,故答案為:{x|x≤-2或x≥3}.



英語翻譯
Aron Ralston is an American man who is interested in
mountainclimbing.Asa mountain climber,Aron is used
to takingrisks.Thisis one of the exciting things
about doing dangeroussports.Therewere many times when
Aron almost lost his life because ofaccidents.OnApril
262003,he found himself in a very dangerous situation
when climbing in Utah.
•;On that day,
Aron’s arm was caught under a 360-Kilo rock that fell on
him when he was climbing by himself in themountains.Becausehe could not free his arm,he stayed there for five
days and hoped that someone would findhim.Butwhen his
water ran out,he knew that he would have to do
something to save his ownlife.Hewasn’t ready to die
thatday.Sohe used his knife to cut off half his right
arm.Then,with his left arm,he bandaged himself so
that he wouldn’t lose too muchblood.Afterthat,he
climbed down the mountain to find help,
•;After losing
his arm,he wrote a book called Between
a Rock and HardPlace.Thismeans being in a difficult situation
that you can’t seem to get outof.Inthis book,Aron
tells of the importance of making good decisions,and of
being in control of one’slife.Hislove for mountain
climbing is so great that he kept on climbing mountains
even after this experience.
•;Do we have the
same spirit as Aron?Let’s think about it before we find
ourselves“between a rock and a hard place”,and before
we have to make a decision that could mean life or
death.


阿隆羅爾斯頓是一個美國男人有興趣
爬山.作為一個登山者,阿隆用
冒險.這是一個令人興奮的事情
做危險的運動.有很多次當
他幾乎失去了他的生命因為事故.四月
262003,他發現自己在一個非常危險的境地
當攀爬在猶他州.
•;那天,
阿隆的手臂被一個360公斤重的岩石落下
他獨自在山上爬.因為他不能自由的手臂,他在那裡呆了五
天,希望有人能找到他.但當他
水跑了出去,他知道他將要做的
一些挽救自己的生命.他還沒準備好去死
那一天.所以他用刀切斷了他一半的權利
臂.然後,用左臂纏著繃帶,他自己
他不會失去太多的血.在那之後,他
爬下山求救,
•;失去後
他的手臂,他寫了一本書叫做之間
岩石和硬的地方.這意味著在一個困難的局面
你似乎不能滾出去的.在這本書中,阿隆
講述了做出好的決策的重要性,並
能控制自己的生活.他愛山
登山是如此之大,他不停地爬山
即使在這方面的經驗.
•;我們有
作為阿隆同樣的精神?讓我們在找到之前想想
我們的“兩難”之間,在
我們不得不做出一個决定,可能意味著生或
死亡.