help me, tui forgot rùi ;-;
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Những câu hỏi liên quan
DH
5
A
1
ND
3
DD
Đoàn Đức Hà
Giáo viên
4 tháng 10 2021
Bài 5*:
\(E\inℤ\Rightarrow2E=\frac{2x+2}{2x+1}=\frac{2x+1+1}{2x+1}=1+\frac{1}{2x+1}\inℤ\Leftrightarrow\frac{1}{2x+1}\inℤ\)
mà \(x\inℤ\Leftrightarrow2x+1\inƯ\left(1\right)=\left\{-1,1\right\}\)
\(\Leftrightarrow x\in\left\{-1,0\right\}\).
Thử lại đều thỏa mãn.
DD
Đoàn Đức Hà
Giáo viên
4 tháng 10 2021
Bài 1:
\(A=\frac{x+15}{x-2}=\frac{x-2+17}{x-2}=1+\frac{17}{x-2}\inℤ\Leftrightarrow\frac{17}{x-2}\inℤ\)
mà \(x\)là số nguyên nên \(x-2\inƯ\left(17\right)=\left\{-17,-1,1,17\right\}\)
\(\Leftrightarrow x\in\left\{-15,1,3,19\right\}\).
Bài 2, 3, 4: Tương tự.
help me please mai mình đi học rùi
17 tháng 7 2021
\(\dfrac{2^8\cdot9^3}{6^4\cdot4^3}=\dfrac{2^8\cdot3^6}{2^4\cdot3^4\cdot2^6}=\dfrac{2^8\cdot3^6}{2^{10}\cdot3^4}=\dfrac{3^2}{2^2}=\dfrac{9}{4}\)
\(12^5\div\left(2^6\cdot3^8\right)=2^{10}\cdot3^5\div\left(2^6\cdot3^8\right)=\dfrac{2^{10}\cdot3^5}{2^6\cdot3^8}=\dfrac{2^4}{3^3}=\dfrac{16}{27}\)
\(\dfrac{3^{12}\cdot2^{14}\cdot5^5}{10^5\cdot6^8\cdot12^4}=\)\(\dfrac{3^{12}\cdot2^{14}\cdot5^5}{5^5\cdot2^5\cdot2^8\cdot3^8\cdot2^8\cdot3^4}=\)\(\dfrac{3^{12}\cdot2^{14}\cdot5^5}{5^5\cdot2^{21}\cdot3^{12}}=\dfrac{1}{2^7}=\dfrac{1}{128}\)
17 tháng 7 2021
1) \(\dfrac{2^8\cdot9^3}{6^4\cdot4^3}=\dfrac{2^8\cdot3^6}{2^4\cdot2^6\cdot3^4}=\dfrac{3^2}{2^2}=\dfrac{9}{4}\)
2) \(12^5:\left(2^6\cdot3^8\right)=\dfrac{2^{10}\cdot3^5}{2^6\cdot3^8}=\dfrac{2^4}{3^3}=\dfrac{16}{27}\)
12 tháng 12 2016
Ta có:\(\frac{a}{b}=\frac{a+c}{b+c}\)
\(\Leftrightarrow a\left(b+c\right)=b\left(a+c\right)\)
\(\Leftrightarrow ab+ac=ab+bc\)
\(\Leftrightarrow ac=bc\)
\(\Leftrightarrow a=b\)
HA
4
10 tháng 5 2017
Our Greener Would will able to have a clean air. It has many green trees around the Earth. Air around the world will not be able to pollute the air. People will not be affected by breathing. So, I love it so much.
Hơi ngắn
10 tháng 5 2017
Our green world will be able to have a clean air. It has many green trees around the Earth. Air around the world will not be able to pollute the air. People will not be affected by breathing. So, I love it so much.
16 tháng 12 2020
câu 6:
Rễ gồm 4 miền: Miền trưởng thành: có chức năng dẫn truyền. Miền hút: hấp thụ nước và muối khoáng. Miền sinh trưởng: làm cho rễ dài ra. Miền chóp rễ: che chở cho đầu rễ.
HV
9 tháng 11 2021
7. | We are excited the first day of school. |
|
| |||||
| A. | at | B. | with | C. | about | D. | in |
8. | My parents often help me at my homework. |
|
| |||||
| A. | at | B. | with | C. | about | D. | in |
9 | I am having a math lesson but I forgot my . I have some difficulty. | |||||||
| A. | calculator | B. | bike | C. | pencil case | D. | pencil sharpener |
10.Look! These pupils are in grade 6. They __________ tall and strong. They __________ football on the school ground.
a. Is / plays b. are / play c. is / is playing d. are / are playing
11. There …………a big table and some chairs ………… the right ………… the bed.
A. is-on-in B. are-on-of C. are-in-on D. is-to-of
12. There are many books and things on the floor. It’s really …………
A. clean B. messy C. interesting D. tidy
13. There aren’t any pillows ………… the bed.
A. on B. in C. behind D. in front of
14. Are there ………… pictures in your bedroom, David?
A. some B. three C. the D. any
15. John ………… his mother cook dinner at 6 p.m.
A. usually help B. usually helps C. help usually D. helps usually
16. Hue lives ………… an apartment ………… Hanoi ………… her uncle and aunt.
A. in-on-at B. at-in-with C. in-in-with D. at-at-near
17. There is a big photoof her family ………… her room’s wall.
A. on B. in C. between D. among
18. It’s called the Riverside Hotel ………… it is near Red River.
A. because B. but C. so D. like
19. Do you often ………… your bicycle to school?
A. drive B. rides C. drives D. ride
20. ………… your favorite subject at school?
A. What B. What’s C. What’re D. Who’s
21. Odd one out :
A.eyes B. mouth C. nose D.feet
CT
11 tháng 2 2022
\(\dfrac{8\times3\times4}{16\times3}\)
\(=\dfrac{8\times3\times2\times2}{8\times2\times3}\)
b) \(\dfrac{30\times25\times7\times8}{75\times8\times12\times14}\)
36 là đúng nhé
tui chọn c