2x - 41 = 33
Tìm x
a) [( 8x - 12 ) : 4] .33=36
b) 41 - 2x+1 = 9
\(a.\left[\left(8x-12\right):4\right]\cdot3^3=3^6\\ \left(8x-12\right):4=3^6:3^3\\ \left(8x-12\right):4=27\\ 8x-12=27\cdot4\\ 8x-12=108\\ 8x=108+12\\ 8x=120\\ x=15\\ b.41-2^{x+1}=9\\ 2^{x+1}=32\\ 2^{x+1}=2^5\\=> x+1=5\\ =>x=4\)
a,[(8x-12):4].33=36
(8x-12):4=36:33
(8x-12):4=33
(8x-12):4=9
8x-12=9.4
8x-12=36
8x=36+12
8x=48
x=6
Vậy x=6
b,41-2x+1=9
2x+1=41-9
2x+1=32
2x+1=25
x+1=5
x=5-1
x=4
Vậy x=4
Chúc bạn học tốt:33
(25.21 + 25.51) : 36
{188 - [ 33 + (62 - 7.3)]}:70
tìm x
(x - 1)(15-3x)=0
720: [ 41-(2x + 5)]=23.5
\(\left(25\cdot21+25\cdot51\right):36\\ =\left[25\cdot\left(21+51\right)\right]:36\\ =\left(25\cdot72\right):36\\ =1800:36\\ =50\\ \left\{188-\left[33+\left(6^2-7\cdot3\right)\right]\right\}:70\\ =\left\{188-\left[33+\left(36-21\right)\right]\right\}:70\\ =\left[188-\left(33+15\right)\right]:70\\ =\left(188-48\right):70\\ =140:70\\ =2\)
\(\left(x-1\right)\left(15-3x\right)=0\\ \Rightarrow\left[{}\begin{matrix}x-1=0\\15-3x=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=1\\3x=15\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=1\\x=5\end{matrix}\right.\)
\(720:\left[41-\left(2x+5\right)\right]=2^3\cdot5=8\cdot5\\ \Rightarrow720:\left[41-\left(2x+5\right)\right]=40\\ \Rightarrow41-\left(2x+5\right)=720:40\\ \Rightarrow41-\left(2x+5\right)=18\\ \Rightarrow2x+5=41-18\\ \Rightarrow2x+5=23\\ \Rightarrow2x=23-5\\ \Rightarrow2x=18\\ \Rightarrow x=18:2\\ \Rightarrow x=9\)
a) (25.21 + 25.51) : 36
= [ 25.( 21 + 51 ) ] : 36
= [ 25. 72 ] : 36
= 1800 : 36
= 50.
Tìm x biết:
a, 2 3 x + 5 2 x = 2 5 2 + 2 3 - 33
b, 260 : x + 4 = 5 2 3 + 5 - 3 3 2 + 2 2
c, 720 : [ 41 - 2 x - 5 ] = 2 3 . 5
d, 3 2 - 2 x - 12 + 35 = 5 2 + 279 : 3 2
a, 2 3 x + 5 2 x = 2 5 2 + 2 3 - 33
8x+25x = 33
33x = 33
x = 1
b, 260 : x + 4 = 5 2 3 + 5 - 3 3 2 + 2 2
260:(x+4) = 5.13–3.13
x+4 = 260:26
x+4 = 10
x = 6
c, 720 : [ 41 - 2 x - 5 ] = 2 3 . 5
41–(2x–5) = 720:40
2x–5 = 41–18
2x = 28
x = 14
d, 3 2 - 2 x - 12 + 35 = 5 2 + 279 : 3 2
7(x–12)+35 = 56
7(x–12) = 21
x–12 = 3
x = 15
what là ............
when là .........
they là ........
their là ..........
what là "Cái gì"
when là "Khi"
they là "Họ"
their là "Của họ"
what:cái gì
when:khi nào
they:họ
their:của họ
Bước tới bàn cô nổi da gà
Mặt mày xanh ngắt mắt hoa hoa
Lơ ngơ dưới lớp tìm bạn giúp
Lác đác bên cô trộm mắt nhìn
Nhớ lúc ở nhà không chịu học
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Cuối tuần xác định nghe cải lương
bài này đc lấy từ bài nào?
Theo t nhớ về kiến thức lớp 7 của t thì có lẽ bà inafy lấy cảm hứng từ bài '' Qua Đèo Ngang '' của Bà Huyện Thanh Quan
Nhảy qua Đèo Ngang bỗng mốt đà
Đập đầu vào đá máu tuôn ra
Lom khom dưới núi tìm y tá
Y tá theo trai không có nhà
Đau đầu chảy máu em sắp chết
Nhìn đi nhìn lại chẳng thấy ai
Khắc lên bia mộ bản thông báo
Nhảy qua Đèo Ngang nhớ lấy đà
Quan sát các mẫu vật xác định vị trí gọi tên các cơ quan của cây và hoàn thành bảng sau
Tên cây?
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Cơ quan quan sát được?
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Mô tả?
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mẫu vật xách định là cái nào
c) x/2=y/3=z/4 và x^2+y^2+2z^2=108
d) x/15=y/20=z/28 và 2x+3y-2=186
Help me !
c, Gọi \(x=2k;y=3k;z=4k\)
Thay vào biểu thức trên ta được :
\(\left(2k\right)^2+\left(3k\right)^2+2\left(4k\right)^2=108\)
\(\Leftrightarrow4k^2+9k^2+32k^2=108\)
\(\Leftrightarrow45k^2=108\Leftrightarrow k^2=2,4\Leftrightarrow k=\pm\sqrt{2,4}\)
tự thay vào nhá :P
d, Áp dụng tính chất dãy tỉ số bằng nhau ta có :
\(\frac{x}{15}=\frac{y}{20}=\frac{z}{28}=\frac{2x+3y-z}{30+60-28}=\frac{186}{62}=3\)
\(x=45;y=60;y=84\)
c) x/2 = y/3 = z/4 => x^2/4 = y^2/9 = z^2/16
Áp dụng tính chất của dãy tỉ số bằng nhau ta có :
x^2/4 = y^2/9 = z^2/16 = x^2 - y^2 + 2z^2 / 4 - 9 + 2 .16 = 108/27 = 4
Suy ra :
x^2/4 = 4 => x^2 = 16 => x = 4 hoặc x = -4
y^2/9 = 4 => y^2 = 36 => y = 6 hoặc y = -6
z^2/16 = 4 => z^2 = 64 => z = 8 hoặc z = -8
d) Ta có : 2x + 3y - 2 = 186 => 2x + 3y = 188
x/15 = y/20 = z/28 = 2x + 3y / 2 . 15 + 3 . 20 = 188/90 = 94/45
Áp dụng tính chất của dãy tỉ số bằng nhau , ta có :
x = 94/45 . 15 = 94/3
y = 94/45 . 20 = 376/9
z = 94/45 . 28 = 2632/45
Vậy x = 94/3 ; y = 376/9 ; z = 2632/45
< III >: Make the correct choice :
1. You can hear BBC news ______ all over the world.
a. shows B. announcements C. receipts D. programs
2. Television can make things _____ because it presents information is an effective way.
a. memory B. memorial C. memorable D. memorably
3. Do you understand this _____? ‘200 WOMEN GIVEN WRONG DIAGNOSIS’
a. report B. headline C. news D. advert
4. Children often prefer looking at _____ to reading books.
a. newspapers B. comics C. articles D. commercials
5. In Britain, there are some ‘terrestrial’ _____ on TV such as BBC1, BBC2, ITV1,...
a. programs B. series C. channels D. cables
6. ‘Is the paper published every day ?’ ‘No, it _____ out once a week.’
a. turns B. goes C. produces D. comes
7. Editorial _____ in ‘The Guardian’ tended to support the government in this matter.
a. comments B. complaints C. commands D. comedies
8. A _____ is a film with factual information, often about a problem in society.
a. series B. soap opera C. documentary D. drama
9. There was a report _____ The Independent _____ this new law.
a. on/ for B. in/ to C. in/ about D. on/ in
10. _____ is a system connecting millions of computer worldwide.
a. The television B. The Internet C. The media D. The phone
11. The scheme allows students from many countries _____ with each other.
a. communicate B. to communicate C. communicating D. communicates
12. _____ the storm warnings, we did not go out last night.
a. Since B. In spite of C. Because of D. The result
13. This is the fifth time you _____ me the same question.
a. ask B. asked C. are asking D. have asked
14. When I arrived at the party, Lucy _____ home.
a. has already gone b. had already gone C. already went D. already was going
15. English people spent 18 hours per week _____ TV.
a. watching B. to watch C. watch D. for watching
16. I’ve lived in a small house near the coast _____ 1990.
a. from B. since C. in D. for
17. She left home in 1993 and _____ since.
a. hasn’t seen B. didn’t see C. hasn’t been seen D. wasn’t seen
18. It’s time we _____ this old car and bought a new one.
a. will sell B. have sold C. had sold D. sold
19. Since Mr. Hassan _____ president, both taxes and unemployment _____.
a. has become/ increased B. became/ increased
c. became/ have increased D. has become have increased
20. _____ all my warnings, he tried to fix the computer himself.
a. Although B. In spite of C. Because D. Instead of
21. Some television programs _____.
a. may make children to be violent. B. make children be violent.
c. may make children violent. D. make children being violent.
22. I _____ away most of my old books when I moved house.
a. threw B. have thrown C. had thrown D. was throwing
23. You _____ whisper. Nobody can hear us.
a. needn’t to B. don’t have to C. mustn’t D. need to
24. The children _____ to the Botanical Garden.
a. were enjoyed taken b. were enjoyed taking C. enjoyed taking D. enjoyed being taken
25. So far this week there _____ three burglaries in our street.
a. are B. were C. have been D. had been
< III >: Make the correct choice :
1. You can hear BBC news ______ all over the world.
a. shows B. announcements C. receipts D. programs
2. Television can make things _____ because it presents information is an effective way.
a. memory B. memorial C. memorable D. memorably
3. Do you understand this _____? ‘200 WOMEN GIVEN WRONG DIAGNOSIS’
a. report B. headline C. news D. advert
4. Children often prefer looking at _____ to reading books.
a. newspapers B. comics C. articles D. commercials
5. In Britain, there are some ‘terrestrial’ _____ on TV such as BBC1, BBC2, ITV1,...
a. programs B. series C. channels D. cables
6. ‘Is the paper published every day ?’ ‘No, it _____ out once a week.’
a. turns B. goes C. produces D. comes
7. Editorial _____ in ‘The Guardian’ tended to support the government in this matter.
a. comments B. complaints C. commands D. comedies
8. A _____ is a film with factual information, often about a problem in society.
a. series B. soap opera C. documentary D. drama
9. There was a report _____ The Independent _____ this new law.
a. on/ for B. in/ to C. in/ about D. on/ in
10. _____ is a system connecting millions of computer worldwide.
a. The television B. The Internet C. The media D. The phone
11. The scheme allows students from many countries _____ with each other.
a. communicate B. to communicate C. communicating D. communicates
12. _____ the storm warnings, we did not go out last night.
a. Since B. In spite of C. Because of D. The result
13. This is the fifth time you _____ me the same question.
a. ask B. asked C. are asking D. have asked
14. When I arrived at the party, Lucy _____ home.
a. has already gone b. had already gone C. already went D. already was going
15. English people spent 18 hours per week _____ TV.
a. watching B. to watch C. watch D. for watching
16. I’ve lived in a small house near the coast _____ 1990.
a. from B. since C. in D. for
17. She left home in 1993 and _____ since.
a. hasn’t seen B. didn’t see C. hasn’t been seen D. wasn’t seen
18. It’s time we _____ this old car and bought a new one.
a. will sell B. have sold C. had sold D. sold
19. Since Mr. Hassan _____ president, both taxes and unemployment _____.
a. has become/ increased B. became/ increased
c. became/ have increased D. has become have increased
20. _____ all my warnings, he tried to fix the computer himself.
a. Although B. In spite of C. Because D. Instead of
21. Some television programs _____.
a. may make children to be violent. B. make children be violent.
c. may make children violent. D. make children being violent.
22. I _____ away most of my old books when I moved house.
a. threw B. have thrown C. had thrown D. was throwing
23. You _____ whisper. Nobody can hear us.
a. needn’t to B. don’t have to C. mustn’t D. need to
24. The children _____ to the Botanical Garden.
a. were enjoyed taken b. were enjoyed taking C. enjoyed taking D. enjoyed being taken
25. So far this week there _____ three burglaries in our street.
a. are B. were C. have been D. had been