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Những câu hỏi liên quan
Bui Dinh Quang
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Phùng Minh Quân
9 tháng 4 2018 lúc 17:18

\(b)\) \(\frac{4}{1.5}+\frac{4}{5.9}+\frac{4}{9.13}+...+\frac{4}{97.101}=\frac{2x+4}{101}\)

\(\Leftrightarrow\)\(\frac{1}{1}-\frac{1}{5}+\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+...+\frac{1}{97}-\frac{1}{101}=\frac{2x+4}{101}\)

\(\Leftrightarrow\)\(1-\frac{1}{101}=\frac{2x+4}{101}\)

\(\Leftrightarrow\)\(\frac{100}{101}=\frac{2x+4}{101}\)

\(\Leftrightarrow\)\(100=2x+4\)

\(\Leftrightarrow\)\(2x=96\)

\(\Leftrightarrow\)\(48\)

Vậy \(x=48\)

Chúc bạn học tốt ~ 

Phùng Minh Quân
9 tháng 4 2018 lúc 17:15

\(a)\) \(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{47.49}=\frac{24}{x+1}\)

\(\Leftrightarrow\)\(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{47.49}=\frac{48}{x+1}\)

\(\Leftrightarrow\)\(\frac{1}{1}-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{47}-\frac{1}{49}=\frac{48}{x+1}\)

\(\Leftrightarrow\)\(1-\frac{1}{49}=\frac{48}{x+1}\)

\(\Leftrightarrow\)\(\frac{48}{49}=\frac{48}{x+1}\)

\(\Leftrightarrow\)\(49=x+1\)

\(\Leftrightarrow\)\(x=48\)

Vậy \(x=48\)

Chúc bạn học tốt ~ 

Nguyễn Thị Xuân Hà
9 tháng 4 2018 lúc 17:21

mình cũng đang bí

Phạm Hoàng Ngọc Thanh
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Justin Bieber
21 tháng 6 2017 lúc 15:50

\(\left(\frac{x+4}{2014}+1\right)+\left(\frac{x+3}{2015}+1\right)=\left(\frac{x+2}{2016}+1\right)+\left(\frac{x+1}{2017}+1\right)\)

\(\frac{x+2018}{2014}+\frac{x+2018}{2015}-\frac{x+2018}{2016}+\frac{x+2018}{2017}=0\)

\(x+2018.\left(\frac{1}{2014}+\frac{1}{2015}-\frac{1}{2016}+\frac{1}{2017}\right)=0\)

\(\Rightarrow x+2018=0\)

\(\Rightarrow x=-2018\)

Lê Minh Anh
21 tháng 6 2017 lúc 15:56

\(\frac{x+4}{2014}+\frac{x+3}{2015}=\frac{x+2}{2016}+\)\(\frac{x+1}{2017}\)

\(\Rightarrow\left(\frac{x+4}{2014}+1\right)+\left(\frac{x+3}{2015}+1\right)=\left(\frac{x+2}{2016}+1\right)+\left(\frac{x+1}{2017}+1\right)\)

\(\Rightarrow\frac{x+2018}{2014}+\frac{x+2018}{2015}=\frac{x+2018}{2016}+\frac{x+2018}{2017}\)

\(\Rightarrow\frac{x+2018}{2014}+\frac{x+2018}{2015}-\frac{x+2018}{2016}-\frac{x+2018}{2017}=0\)

\(\Rightarrow\left(x+2018\right)\left(\frac{1}{2014}+\frac{1}{2015}+\frac{1}{2016}+\frac{1}{2017}\right)=0\)

\(M\text{à:}\frac{1}{2014}+\frac{1}{2015}-\frac{1}{2016}-\frac{1}{2017}\ne0\)

\(\Rightarrow x+2018=0\Rightarrow x=-2018\)

Phương Trình Hai Ẩn
21 tháng 6 2017 lúc 15:59

\(\left(\frac{x+4}{2014}+1\right)+\left(\frac{x+3}{2015}+1\right)=\left(\frac{x+2}{2016}+1\right)+\left(\frac{x+1}{2017}+1\right)\)

\(\Rightarrow\frac{x+2018}{2014}+\frac{x+2018}{2015}=\frac{x+2018}{2016}+\frac{x+2018}{2017}\)

\(\Rightarrow\frac{x+2018}{2014}+\frac{x+2018}{2015}-\frac{x+2018}{2016}-\frac{x+2018}{2017}=0\)

\(\Rightarrow\left(x+2018\right).\left(\frac{1}{2014}+\frac{1}{2015}-\frac{1}{2016}-\frac{1}{2017}\right)=0\)

=> x+2018=0

=> x=-2018

Văn Trọng Khôi
Xem chi tiết
Gil Lê
Xem chi tiết
Phùng Minh Quân
20 tháng 4 2018 lúc 8:40

Bài 3 : 

\(\frac{x-1}{2016}+\frac{x-2}{2015}=\frac{x-3}{2014}+\frac{x-4}{2013}\)

\(\Leftrightarrow\)\(\left(\frac{x-1}{2016}-1\right)+\left(\frac{x-2}{2015}-1\right)=\left(\frac{x-3}{2014}-1\right)+\left(\frac{x-4}{2013}-1\right)\)

\(\Leftrightarrow\)\(\frac{x-1-2016}{2016}+\frac{x-2-2015}{2015}=\frac{x-3-2014}{2014}+\frac{x-4-2013}{2013}\)

\(\Leftrightarrow\)\(\frac{x-2017}{2016}+\frac{x-2017}{2015}=\frac{x-2017}{2014}+\frac{x-2017}{2013}\)

\(\Leftrightarrow\)\(\frac{x-2017}{2016}+\frac{x-2017}{2015}-\frac{x-2017}{2014}-\frac{x-2017}{2013}=0\)

\(\Leftrightarrow\)\(\left(x-2017\right)\left(\frac{1}{2016}+\frac{1}{2015}-\frac{1}{2014}-\frac{1}{2013}\right)=0\)

Vì \(\frac{1}{2016}+\frac{1}{2015}-\frac{1}{2014}-\frac{1}{2013}\ne0\)

Nên \(x-2017=0\)

\(\Rightarrow\)\(x=2017\)

Vậy \(x=2017\)

Chúc bạn học tốt ~ 

Phùng Minh Quân
20 tháng 4 2018 lúc 8:30

Bài 1 : 

\(\left(8x-5\right)\left(x^2+2014\right)=0\)

\(\Leftrightarrow\)\(\orbr{\begin{cases}8x-5=0\\x^2+2014=0\end{cases}\Leftrightarrow\orbr{\begin{cases}8x=0+5\\x^2=0-2014\end{cases}}}\)

\(\Leftrightarrow\)\(\orbr{\begin{cases}8x=5\\x^2=-2014\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{5}{8}\\x=\sqrt{-2014}\left(loai\right)\end{cases}}}\)

Vậy \(x=\frac{5}{8}\)

Chúc bạn học tốt ~ 

Phùng Minh Quân
20 tháng 4 2018 lúc 8:36

Bài 2 : 

\(\frac{2-x}{2015}-1=\frac{1-x}{2016}-\frac{x}{2017}\)

\(\Leftrightarrow\)\(\frac{2-x}{2015}+1=\left(\frac{1-x}{2016}+1\right)-\left(\frac{x}{2017}-1\right)\) ( cộng 2 vế cho 2 ) 

\(\Leftrightarrow\)\(\frac{2-x+2015}{2015}=\frac{1-x+2016}{2016}-\frac{x-2017}{2017}\)

\(\Leftrightarrow\)\(\frac{2017-x}{2015}=\frac{2017-x}{2016}+\frac{2017-x}{2017}\)

\(\Leftrightarrow\)\(\frac{2017-x}{2015}-\frac{2017-x}{2016}-\frac{2017-x}{2017}=0\)

\(\Leftrightarrow\)\(\left(2017-x\right)\left(\frac{1}{2015}-\frac{1}{2016}-\frac{1}{2017}\right)=0\)

Vì \(\frac{1}{2015}-\frac{1}{2016}-\frac{1}{2017}\ne0\)

Nên \(2017-x=0\)

\(\Rightarrow\)\(x=2017\)

Vậy \(x=2017\)

Chúc bạn học tốt ~ 

Huy Anh
Xem chi tiết
Hà Quỳnh An
Xem chi tiết
Phùng Tuệ Minh
27 tháng 9 2019 lúc 20:08

\(\frac{x+1}{2018}+\frac{x+2}{2017}+\frac{x+3}{2016}=\frac{x+4}{2015}+\frac{x+5}{2014}+\frac{x+6}{2013}\)

\(\Leftrightarrow\) \(\frac{x+1}{2018}+1+\frac{x+2}{2017}+1+\frac{x+3}{2016}+1=\frac{x+4}{2015}+1+\frac{x+5}{2014}+1+\frac{x+6}{2013}+1\)

\(\Leftrightarrow\frac{x+2019}{2018}+\frac{x+2019}{2017}+\frac{x+2019}{2016}=\frac{x+2019}{2015}+\frac{x+2019}{2014}+\frac{x+2019}{2013}\)

\(\Leftrightarrow\frac{x+2019}{2018}+\frac{x+2019}{2017}+\frac{x+2019}{2016}-\frac{x+2019}{2015}-\frac{x+2019}{2014}-\frac{x+2019}{2013}=0\)

\(\Leftrightarrow\left(x+2019\right)\left(\frac{1}{2018}+\frac{1}{2017}+\frac{1}{2016}-\frac{1}{2015}-\frac{1}{2014}-\frac{1}{2013}\right)\)\(=0\)

Lại có: \(\frac{1}{2018}+\frac{1}{2017}+\frac{1}{2016}-\frac{1}{2015}-\frac{1}{2014}-\frac{1}{2013}\) \(\ne\) \(0\)

\(\Rightarrow x+2019=0\)
\(\Rightarrow x=0-2019=-2019\)

Vậy x= -2019

Hue Tran
Xem chi tiết
Trần Minh Hoàng
30 tháng 6 2020 lúc 9:00

PT đã cho tương đương với:

\(\left(\frac{x}{2017}+1\right)+\left(\frac{x+1}{2016}+1\right)=\left(\frac{x+2}{2015}+1\right)+\left(\frac{x+3}{2014}+1\right)\)

\(\Leftrightarrow\frac{x+2017}{2017}+\frac{x+2017}{2016}=\frac{x+2017}{2015}+\frac{x+2017}{2014}\)

\(\Leftrightarrow\left(x+2017\right)\left(\frac{1}{2017}+\frac{1}{2016}\right)=\left(x+2017\right)\left(\frac{1}{2015}+\frac{1}{2014}\right)\)

\(\Leftrightarrow x+2017=0\Leftrightarrow x=-2017\)

Nguyễn Lê Phước Thịnh
30 tháng 6 2020 lúc 12:23

Ta có: \(\frac{x}{2017}+\frac{x+1}{2016}=\frac{x+2}{2015}+\frac{x+3}{2014}\)

\(\Leftrightarrow\frac{x}{2017}+1+\frac{x+1}{2016}+1=\frac{x+2}{2015}+1+\frac{x+3}{2014}+1\)

\(\Leftrightarrow\frac{x+2017}{2017}+\frac{x+2017}{2016}=\frac{x+2017}{2015}+\frac{x+2017}{2014}\)

\(\Leftrightarrow\frac{x+2017}{2017}+\frac{x+2017}{2016}-\frac{x+2017}{2015}-\frac{x+2017}{2014}=0\)

\(\Leftrightarrow\left(x+2017\right)\left(\frac{1}{2017}+\frac{1}{2016}-\frac{1}{2015}-\frac{1}{2014}\right)=0\)

\(\frac{1}{2017}+\frac{1}{2016}-\frac{1}{2015}-\frac{1}{2014}\ne0\)

nên x+2017=0

hay x=-2017

Vậy: S={-2017}

Đỗ Thị Ngọc Ánh
Xem chi tiết
Lê Tuấn Anh
Xem chi tiết
Bùi Anh Tuấn
18 tháng 2 2020 lúc 15:01

\(\frac{x+1}{2016}-\frac{x+2}{2015}=\frac{x+2017}{2014}\)

\(\frac{x+1+2016}{2016}-\frac{x+2+2015}{2015}-\frac{x+2017}{2014}=0\)

\(\frac{x+2017}{2016}-\frac{x+2017}{2015}-\frac{x+2017}{2014}=0\)

\(\left(x+2017\right)\left(\frac{1}{2016}-\frac{1}{2015}-\frac{1}{2014}\right)=0\)

Vì \(\left(\frac{1}{2016}-\frac{1}{2015}-\frac{1}{2014}\right)\ne0\)

\(\Rightarrow x+2017=0\)

\(\Rightarrow x=-2017\)

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