cứu e với 6h30 hc ròi nuh
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GN
GV Nguyễn Trần Thành Đạt
Giáo viên
28 tháng 11 2023
\(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\\a, 2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\\ n_{H_2}=n_{H_2SO_4}=\dfrac{3}{2}.0,2=0,3\left(mol\right)\\ b,V_{H_2\left(đktc\right)}=0,3.22,4=6,72\left(l\right)\\ c,n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}.0,2=0,1\left(mol\right)\\ m_{Al_2\left(SO_4\right)_3}=0,1.342=34,2\left(g\right)\\ d,C\%_{ddH_2SO_4}=\dfrac{0,3.98}{200}.100\%=14,7\%\\ e,m_{ddmuoi}=5,4+200-0,3.2=204,8\left(g\right)\\ C\%_{ddAl_2\left(SO_4\right)_3}=\dfrac{34,2}{204,8}.100\%\approx16,699\%\)
28 tháng 11 2023
\(a)2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\\ b)n_{Al}=\dfrac{5,4}{27}=0,2mol\\ 2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(0,2-\rightarrow0,3--\rightarrow0,1--\rightarrow0,3\)
\(m_{H_2}=0,3.2=0,6g\\ c)m_{Al_2\left(SO_4\right)_3}=0,1.342=34,2g\\ d)C_{\%H_2SO_4}=\dfrac{0,3.98}{200}\cdot100=14,7\%\\ e)C_{\%Al_2\left(SO_4\right)_3}=\dfrac{34,2}{5,4+200-0,6}\cdot100=16,7\%\)
9 tháng 1
Gọi số lớn nhất cần tìm là x
\(5=5;9=3^2\)
=>\(BCNN\left(5;9\right)=5\cdot3^2=45\)
Vì x là số có 3 chữ số nên 100<=x<=999
x chia hết cho 5 và 9 nên \(x\in BC\left(5;9\right)\)
=>\(x\in B\left(45\right)\)
mà 100<=x<=999
nên \(x\in\left\{135;180;225;...;900;945;990\right\}\)(1)
Vì x không chia hết cho 2 nên x lẻ(2)
từ (1) và (2) suy ra \(x\in\left\{135;225;315;...;945\right\}\)
mà x là số lớn nhất
nên x=945
giúp em 3 bài này với ạ em đang cần gấp chiều em hc ròi ạ ai làm đc bài nào thì gửi luôn giúp em ạ
M
1
NP
Ngô Phương
Admin
VIP
20 tháng 12 2022
didn't stay
Cấu trúc thì quá khứ đơn
(-) S + did not + V(không chia).
TN
25 tháng 6 2017
\(x^2+2x+5=\left(x^2+2x+1\right)+4=\left(x+1\right)^2+4\ge4\)Vậy GTNN của biểu thức là 4 khi \(x+1=0\Rightarrow x=-1\)
\(b,2x-x^2-4=-\left(x^2-2x+1\right)-3=-\left(x-1\right)^2-3\le-3\)Vậy GTLN của biểu thức là -3 khi \(x-1=0\Rightarrow x=1\)
25 tháng 6 2017
a) Đặt \(A=x^2+2x+5\)
\(A=\left(x^2+2.x.1+1^2\right)+4\)
\(A=\left(x+1\right)^2+4\)
Ta có : \(\left(x+1\right)^2\ge0\forall x\)
\(\Leftrightarrow\left(x+1\right)^2+4\ge4\)
Vậy \(Min_A=4\Leftrightarrow x=-1.\)
b ) Đặt \(B=2x-x^2-4\)
\(B=-x^2+2x-4\)
\(B=-\left(x^2-2x+4\right)\)
\(B=-\left(x^2-2.x.1+1^2\right)+3\)
\(B=-\left(x-1\right)^2-3\)
Ta có : \(\left(x-1\right)^2\ge0\forall x\)
\(\Leftrightarrow-\left(x-1\right)^2\le0\forall x\)
\(\Leftrightarrow-\left(x-1\right)^2-3\le-3\)
Vậy \(Max_B=-3\Leftrightarrow x=1.\)
DN
29 tháng 12 2017
f(x)+g(x)=(x5-3x2+7x4-9x3+x2-1/4.x)+(5x4-x5+x2-2x3+3x2-1/4)=(x5-x5)+(7x4+5x4)+(-9x3-2x3)+(-3x2+x2+3x2+x2)+(-1/4.x)-1/4=12x4-11x3+2x2-1/4.x-1/4
f(x)-g(x)=(x5-3x2+7x4-9x3+x2-1/4.x)-(5x4-x5+x2-2x3+3x2-1/4)=(x5+x5)+(7x4-5x4)+(-9x3+2x3)+(-3x2+x2-3x2-x2)+(-1/4.x)+1/4=2x5+2x4-7x3-6x2-1/4.x+1/4
LN
14 tháng 10 2021
a, Giả sử: Cz // Ax // By
Do Cz // Ax \(\Rightarrow\widehat{A}+\widehat{C_1}=180^o\)(2 góc TCP)
\(\Rightarrow80^o+\widehat{C_1}=180^o\)
\(\Rightarrow\widehat{C_1}=180^o-80^o=100^o\)
Do Cz // By \(\Rightarrow\widehat{C_2}=\widehat{B}=35^o\)(2 góc so le trong)
Ta thấy: \(\widehat{ACB}=\widehat{C_1}+\widehat{C_2}=100^o+35^o=135^o\)
b, Do d // AC \(\Rightarrow\widehat{ACB}+\widehat{EBC}=180^o\)(2 góc TCP)
\(\Rightarrow135^o+\widehat{EBC}=180^o\)
\(\Rightarrow\widehat{EBC}=180^o-135^o=45^o\)
26 tháng 11 2018
The Pagoda of the Celestial Lady (Vietnamese: Chùa Thiên Mụ; also called Linh Mụ Pagoda) is a historic temple in the city of Huế in Vietnam. Its iconic seven-story pagoda is regarded as the unofficial symbol of the city,[1] and the temple has often been the subject of folk rhymes and ca dao about Huế.[2]
The pagoda sits on the Hà Khê hill, in the ward of Hương Long in Huế. It is around 3 kilometres (1.9 mi) from the Citadel of Huế constructed by the Nguyễn Dynasty and sits on the northern bank of the Perfume River.[2][1]
Built in 1601 on the order of the first Nguyễn lords, Nguyễn Hoàng, who at that time was the governor of Thuận Hóa (now known as Huế). The Nguyen Lords were in name, officials of the ruling Lê Dynasty in Hanoi, but was the de factoindependent ruler of central Vietnam. According to the royal annals, Hoang while touring the vicinity, was told of the local legend in which an old lady, known as Thiên Mụ (literally "celestial lady"), dressed in red and blue sat at the site, rubbing her cheeks. She foretold that a lord would come and erect a pagoda on the hill to pray for the country's prosperity. She then vanished after making her prophecy. Upon hearing this, Hoang ordered the construction of a temple at the site, thus the beginning of Thiên Mụ Tự.[2][1]
The original temple was simply constructed, then later expanded and refurbished. In 1665, major construction was undertaken by the Nguyễn Lord Nguyễn Phúc Tần.[2]
11 tháng 9 2023
Bài 5:
1. There are a few students taking part in the event
→ There aren't many students taking part in the event.
2. If he doesn't work hard, he will lose his job
→ Unless he works hard, he will lose his job.
3. Let's write about the three Rs ?
→ Why don't we write about the three Rs?
4. Learning about recyking is fun
→ It's fun to learn about recycling.
5. It's not good to throw old clothes away
→ You shouldn't throw old clothes away
Xếp từ thành câu
Bài 1
1. they / to / movies / do / how / go / the / often ?
→ How often do they go to the movies?
2. your eyes / swimming / should / when goggles / you / you / go / wear / to protect
→ When you go swimming, you should wear goggles to protect your eyes.
3. usually / his / swimming / with / friends / he / goes
→ He usually goes swimming with his friends.
4. go / do / weekend / on / always / fishing / parents / their ?
→ Do their parents always go fishing on the weekend?
5. camping / they / go / do / sometimes
→ Sometimes they go camping.
6. what / TV / you / do / on / sports / watch?
→ What sports do you watch on TV?
Bài 2
1. Our / important / an / sports and games / in play / lives / part
→ Sports and games play an important part in our lives.
2. players / how / match / there / in / many / are / football / a ?
→ How many players are there in a football match?
3. by / she / to keep / every day / tries / fit / jogging
→ She tries to keep fit by jogging every day.
4. yesterday / who / play / football / you / did / with ?
→ Who did you play football with yesterday?
5. sports / building / physical and strength / necessary / are / for
→ Sports are necessary for building physical strength.
6. to switch / before / go / don't / the TV / off / you / forget / to bed
→ Don't forget to switch off the TV before you go to bed.
7. Sunday / I / usually / friends / swimming / on / go / mornings / with / my
→ On Sunday mornings, I usually go swimming with my friends.
8. match / you / on / the / did / television / last night / watch / basketball / the ?
→ Did you watch the basketball match on television last night?
Bài 1:
a: \(x+\dfrac{5}{4}=\dfrac{-1}{2}\)
=>\(x=-\dfrac{1}{2}-\dfrac{5}{4}=-\dfrac{2}{4}-\dfrac{5}{4}=-\dfrac{7}{4}\)
b: \(\dfrac{3}{8}-x=\dfrac{2}{3}\)
=>\(x=\dfrac{3}{8}-\dfrac{2}{3}=\dfrac{9}{24}-\dfrac{16}{24}=-\dfrac{7}{24}\)
c: \(-x+\dfrac{1}{5}=2\dfrac{2}{5}\)
=>\(\dfrac{1}{5}-x=\dfrac{12}{5}\)
=>\(x=\dfrac{1}{5}-\dfrac{12}{5}=-\dfrac{11}{5}\)
d: \(\dfrac{2}{3}x+\dfrac{7}{10}=\dfrac{3}{10}\)
=>\(x\cdot\dfrac{2}{3}=\dfrac{3}{10}-\dfrac{7}{10}=-\dfrac{4}{10}=-\dfrac{2}{5}\)
=>\(x=-\dfrac{2}{5}:\dfrac{2}{3}=-\dfrac{2}{5}\cdot\dfrac{3}{2}=-\dfrac{3}{5}\)
e: \(\dfrac{1}{2}-3x=-\dfrac{2}{5}\)
=>\(3x=\dfrac{1}{2}+\dfrac{2}{5}=\dfrac{5}{10}+\dfrac{4}{10}=\dfrac{9}{10}\)
=>\(x=\dfrac{9}{10}:3=\dfrac{3}{10}\)
f: \(\dfrac{-3}{11}-\left(x-\dfrac{2}{5}\right)=-\dfrac{14}{22}\)
=>\(\dfrac{-3}{11}-\left(x-\dfrac{2}{5}\right)=-\dfrac{7}{11}\)
=>\(x-\dfrac{2}{5}=-\dfrac{3}{11}+\dfrac{7}{11}=\dfrac{4}{11}\)
=>\(x=\dfrac{4}{11}+\dfrac{2}{5}=\dfrac{20}{55}+\dfrac{22}{55}=\dfrac{42}{55}\)
g: \(\dfrac{7}{2}-\left[\dfrac{3}{2}-\left(x+\dfrac{7}{2}\right)\right]=-\dfrac{9}{11}\)
=>\(\dfrac{7}{2}-\dfrac{3}{2}+x+\dfrac{7}{2}=-\dfrac{9}{11}\)
=>\(x+\dfrac{11}{2}=-\dfrac{9}{11}\)
=>\(x=-\dfrac{9}{11}-\dfrac{11}{2}=\dfrac{-18}{22}-\dfrac{121}{22}=\dfrac{-139}{22}\)