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* Tác hại của nó chính là: Những biểu hiện trên chứng tỏ đó là những học sinh chưa có tính kỉ luật, thiếu sự tôn trọng thầy cô giáo cũng như bạn bè, không coi trọng đến những nội quy, quy định của trường lớp. Hình thành nên tính thiếu trung thực, gian lận, không coi trọng phẩm chất đạo đức của mình dẫn đến thiếu tính kỉ luật. Nếu không sửa chữa lại những hành vi đó thì khó có thể thành một người con ngoan trò giỏi được thầy yêu bạn mến.
1.I think you ought to give up playing video games. (should)
-->I think you should give up playing video games.
2.It's necessary for me to finish the work on time. (have to)
--->I have to finish the work on time.
3.It wasn't necessary for you to clean that car. (have to)
--->You didn't have to clean that car.
4.It was quite unnecessary for you to adopt a green lifestyle. (have to)
---->You didn't have to adopt a green lifestyle.
5.It was careless of you to leave the windows open last night. (shouldn't)
----->You shouldn't have left the windows open last night.
6.It is advisable for each member in the family to share the housework equally. (should)
---->Each member in the family should share the housework equally.
7.You are required to come back home before 10 p.m. (must)
--->You must come back home before 10 p.m.
8.Lina is advised to prepare carefully in the morning. (should)
----->Lina should prepare carefully in the morning.
9.Tu is responsible for picking up litter. (have to)
------>Tu has to pick up litter.
1.You are required to ask your parents for permission before staying out late. (must)
You must ask your parents for permission before staying out late.
2.I think you ought to give up smoking immediately. (should)
I think you should give up smoking immediately.
3.It is not a good idea for me to stay up late. (shouldn't)
I shouldn't stay up late.
4.It wasn't necessary for you to send these letters. (have to)
You didn't have to send these letters.
5.It was unnecessary for Tim to finish the work. (have to)
Tim didn't have to finish the work.
6.It was careless of you to leave your children alone at home. (shouldn't)
You shouldn't have left your children alone at home.
Bằng 1 cách nào đó 1 câu hỏi từ 2023 ở đây và tôi vẫn trả lời nó sau 1 năm :v
Câu 6: Để hàm số y=(1-m)x+3 nghịch biến trên R thì 1-m<0
=>m>1
=>Chọn B
Câu 7: D
Câu 10: (D)//(D')
=>\(\left\{{}\begin{matrix}3m+1=2\left(m+1\right)\\-2\ne-2\left(loại\right)\end{matrix}\right.\Leftrightarrow m\in\varnothing\)
=>Chọn D
Câu 11: \(x^2+2x+2=\left(x+1\right)^2+1>=1>0\forall x\)
=>\(\sqrt{x^2+2x+2}\) luôn xác định với mọi số thực x
=>Chọn A
Câu 12: Để hai đường thẳng y=x+3m+2 và y=3x+2m+3 cắt nhau tại một điểm trên trục tung thì \(\left\{{}\begin{matrix}1\ne3\left(đúng\right)\\3m+2=2m+3\end{matrix}\right.\)
=>3m+2=2m+3
=>m=1
=>Chọn C
Câu 3:
a: \(BD=\sqrt{BC^2-DC^2}=4\left(cm\right)\)
b: \(\widehat{A}=180^0-2\cdot70^0=40^0< \widehat{B}\)
nên BC<AC=AB
c: Xét ΔEBC vuông tại E và ΔDCB vuông tại D có
BC chung
\(\widehat{EBC}=\widehat{DCB}\)
Do đó:ΔEBC=ΔDCB
d: Xét ΔOBC có \(\widehat{OBC}=\widehat{OCB}\)
nên ΔOBC cân tại O
Câu 2
a) Thay y = -2 vào biểu thức đã cho ta được:
2.(-2) + 3 = -1
Vậy giá trị của biểu thức đã cho tại y = -2 là -1
b) Thay x = -5 vào biểu thức đã cho ta được:
2.[(-5)² - 5] = 2.(25 - 5) = 2.20 = 40
Vậy giá trị của biểu thức đã cho tại x = -5 là 40
PTHH : 2Al + 6HCl --> 2AlCl3 + 3H2 ↑ (1)
nAlCl3 = \(\dfrac{m}{M}=\dfrac{13,35}{27+35,5.3}=0.1\left(mol\right)\)
Từ (1) => nHCl = 2nH2 = 0.2 (mol)
=> mHCl = n.M = 0.2 x 36.5 = 7.3 (g)
\(PTHH:2Al+6HCl\rightarrow2AlCl_3+3H_2\\ n_{AlCl_3}=\dfrac{m}{M}=\dfrac{13,35}{133,5}=0,1\left(mol\right)\\ Theo.PTHH:n_{HCl}=3.n_{AlCl_3}=3.0,1=0,3\left(mol\right)\\ m_{HCl}=n.M=0,3.36,5=10,95\left(g\right)\)
Lời giải:
$(x-15)-x.13=0$
$x-15-x.13=0$
$(x-x.13)-15=0$
$x(1-13)-15=0$
$x.(-12)-15=0$
$x.(-12)=15$
$x=15:(-12)=\frac{-5}{4}$
1 Japanese is too difficult for me to learn
2 If he felt well, he wouldn't go to bed early
3 I wish I hadn't gone out in the rain
4 They had me carry te box upstairs
5 Your sister is too young to enjoy this film
6 THey had this letter posted by me
7 The morning was too cold for them to go out
8 If the tickets were cheap enough, we would go there
9 The pupils collected these old clothes
10 The coffee is so excellent so I can drink it
11 Her house was sold 2 years ago
12 Some tickets was bought there by him
13 Waste paper was recycled to save money and labour
14 The TV set was so heavy that the girl couldn't move it
15 I will have someone type the report for you
16 There was so much fog that the driver couldn't see far
17 THe day was fine enoigh for them to enjoy sunbathing on the beach
18 I wish your were here now
19 Susan offeref me to lend her some money
20 They asked me is I could fill in the form
a) \(\left(x-5\right):7=0\)
\(\Rightarrow x-5=0\)
\(\Rightarrow x=5\)
b) \(\left(x-5\right):3+3=24\)
\(\Rightarrow\left(x-5\right):3=21\)
\(\Rightarrow x-5=63\)
\(\Rightarrow x=68\)
c) \(\left(45-9x\right)\left(x.5-15\right)=0\)
\(\Rightarrow\orbr{\begin{cases}45-9x=0\\x.5-15=0\end{cases}}\Rightarrow\orbr{\begin{cases}9x=45\\x.5=15\end{cases}}\Rightarrow\orbr{\begin{cases}x=5\\x=3\end{cases}}\)
d) \(3\left(x-7\right)-2=100\)
\(\Rightarrow3\left(x-7\right)=102\)
\(\Rightarrow x-7=34\)
\(\Rightarrow x=41\)