K
Khách

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

24 tháng 9 2021

3n+1  = 27

=> 3n+1 = 33

=> n+1 =3

=> n= 3-1

=> n=2

Vậy n =2 

Sửa đề: \(\dfrac{16}{15}\rightarrow\dfrac{16}{25}\) 

Giải:

\(\left(x-\dfrac{3}{5}\right)^2=\dfrac{16}{25}\) 

\(\Rightarrow\left[{}\begin{matrix}\left(x-\dfrac{3}{5}\right)^2=\left(\dfrac{4}{5}\right)^2\\\left(x-\dfrac{3}{5}\right)^2=\left(\dfrac{-4}{5}\right)^2\end{matrix}\right.\) 

\(\Rightarrow\left[{}\begin{matrix}x-\dfrac{3}{5}=\dfrac{4}{5}\\x-\dfrac{3}{5}=\dfrac{-4}{5}\end{matrix}\right.\) 

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{7}{5}\\x=\dfrac{-1}{5}\end{matrix}\right.\) 

 

\(\left(\dfrac{5}{3}-x\right)^3=\dfrac{1}{27}\) 

\(\Rightarrow\left(\dfrac{5}{3}-x\right)^3=\left(\dfrac{1}{3}\right)^3\) 

            \(\dfrac{5}{3}-x=\dfrac{1}{3}\) 

                    \(x=\dfrac{5}{3}-\dfrac{1}{3}\) 

                    \(x=\dfrac{4}{3}\)

12 tháng 3 2022

tối giản rồi bn

12 tháng 3 2022

tối giản rồi mà bạn

27 tháng 8 2021

\(\left(4x-1\right)^3=27\Leftrightarrow4x-1=3\Leftrightarrow4x=4\Leftrightarrow x=1\)

27 tháng 8 2021

\(\left(4x-1\right)^3=27\\ \Leftrightarrow\left(4x-1\right)^3=3^3\\ \Leftrightarrow4x-1=3\\ \Leftrightarrow4x=4\\ \Leftrightarrow x=1\)

NM
14 tháng 2 2021

ta có 

\(lim\frac{\sqrt{n+4}}{\sqrt{n}+1}=lim\frac{\sqrt{n+4}:\sqrt{n}}{\left(\sqrt{n}+1\right):\sqrt{n}}=lim\frac{\sqrt{1+\frac{4}{n}}}{1+\frac{1}{\sqrt{n}}}=1\)

6 tháng 11 2021

mng giúp với

 

 

6 tháng 11 2021

\(\Leftrightarrow7x\left(x+5\right)+\left(x-5\right)\left(x+5\right)=0\\ \Leftrightarrow\left(x-5\right)\left(7x+x+5\right)=0\\ \Leftrightarrow\left(x-5\right)\left(8x+5\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=5\\x=-\dfrac{5}{8}\end{matrix}\right.\)

\(\Leftrightarrow x^2+x-5x-5-x^2-6x-9-6=0\\ \Leftrightarrow-10x-20=0\\ \Leftrightarrow x=-2\)

b: Ta có: \(N=a^3+b^3+3ab\)

\(=\left(a+b\right)^3-3ab\left(a+b\right)+3ab\)

\(=1-3ab+3ab\)

=1

11 tháng 9 2023

I. Write sentences with the cues given

1. Mai / usually / listen / K - pop music / free time.

→ Mai usually listens to K-pop music in her free time.

2. when / I / be / a child / I / enjoy / play / computer games

→ When I was a child, I enjoyed playing computer games.

3. my father / spend / most / spare time / look after / the garden

→ My father spends most of his spare time looking after the garden.

4. watching TV / most / popular / leisure activity / Britain ?

→ Is watching TV the most popular leisure activity in Britain?

5. many teenagers / addicted / the Internet / computer games 

→ Many teenagers are addicted to the Internet and computer games.

6. she / get / hooked / the medical drama / after / watch / the first people 

→ She got hooked on the medical drama after watching the first episode.

7. most / my friends / prefer / play sports / to / surf the net

→ Most of my friends prefer to play sports rather than surf the net.

8. today's world  / teenagers / rely / technology / more / the past 

→ In today's world, teenagers rely on technology more than in the past

II. Write the second sentences so that it has a similar meaning to the first one

1. It takes us more than two hours to see the film " Avatar "

→ The film " Avatar " requires more than two hours of our time to watch.

2. She likes to hang out with friends on Saturday evening

→ She's interested in socializing with friends on Saturday evening

Câu 4: 

Số quả dưa là:

\(15:\dfrac{3}{11}=15\cdot\dfrac{11}{3}=55\)(quả)