K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

28 tháng 12 2021

11 He asked his daughter what kind of sport were you interested in  

12 I asked the neighboor what time your husband left for work 

13) You hate watching violent films , don't you ?

14) They have just repaired the street ìn front of my house,haven't they ?

15) The first TV picture wasn't produced by Baird in 1926,did he ?

16) This kind of shoes was bought last year,didn't she 

28 tháng 12 2021

My mom asked me how your course took

The man asked me how many students in the class were there 

 

23 tháng 2 2023

a: Khi m=3 thì (1): x^2-6x+4=0

=>x^2-6x+9-5=0

=>(x-3)^2=5

=>\(x=3\pm\sqrt{5}\)

NV
28 tháng 12 2021

26.

\(\sqrt{\dfrac{-3}{2a^3}}=\sqrt{\dfrac{-3a}{2a^4}}=\dfrac{1}{a^2}\sqrt{\dfrac{-3a}{2}}\)

Đáp án B

28.

\(\sqrt{\dfrac{a^3}{a}}=\sqrt{a^2}=\left|a\right|=-a\)

Đáp án B

b: Để A nguyên thì \(x+2\in\left\{1;-1\right\}\)

hay \(x\in\left\{-1;-3\right\}\)

Để B nguyên thì \(\sqrt{x}-1\in\left\{-1;1;2;3;6\right\}\)

\(\Leftrightarrow\sqrt{x}\in\left\{0;2;3;4;7\right\}\)

hay \(x\in\left\{0;4;9;16;49\right\}\)

30 tháng 9 2021

a) Ta có: \(\dfrac{a}{3b+c}=\dfrac{b}{a+3c}=\dfrac{c}{3a+b}=\dfrac{a+b+c}{3b+c+a+3c+3a+b}=\dfrac{a+b+c}{4\left(a+b+c\right)}=\dfrac{1}{4}\)

\(\Rightarrow\left\{{}\begin{matrix}3b+c=4a\\a+3c=4b\\3a+b=4c\end{matrix}\right.\)

\(\Rightarrow\dfrac{3b+c}{a}+\dfrac{a+3c}{b}+\dfrac{3a+b}{c}=\dfrac{4a}{a}+\dfrac{4b}{b}+\dfrac{4c}{c}=4+4+4=12\)

b) \(A=\dfrac{x+1}{x+2}=\dfrac{x+2}{x+2}-\dfrac{1}{x+2}=1-\dfrac{1}{x+2}\in Z\)

\(\Rightarrow\left(x+2\right)\inƯ\left(1\right)=\left\{-1;1\right\}\)

\(\Rightarrow x\in\left\{-3;-1\right\}\)

\(B=\dfrac{\sqrt{x}+5}{\sqrt{x}-1}\left(đk:x\ge0\right)=1+\dfrac{6}{\sqrt{x}-1}\in Z\)

\(\Rightarrow\sqrt{x}-1\inƯ\left(6\right)=\left\{-6;-3;-2;-1;1;2;3;6\right\}\)

Do \(x\ge0,x\in Z\)

\(\Rightarrow x\in\left\{0;4;9;16;49\right\}\)