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5 tháng 3 2019

\(\frac{x-3}{2017}-\frac{x-2}{2018}=\frac{x-2018}{2}+\frac{x-2017}{3}\)

\(\Leftrightarrow\frac{x-3}{2017}-1-\frac{x-2}{2018}-1=\frac{x-2018}{2}-1+\frac{x-2017}{3}-1\)

\(\Leftrightarrow\frac{x-2020}{2017}-\frac{x-2020}{2018}=\frac{x-2020}{2}+\frac{x-2020}{3}\)

\(\Leftrightarrow\frac{x-2020}{2017}-\frac{x-2020}{2018}-\frac{x-2020}{2}-\frac{x-2020}{3}=0\)

\(\Leftrightarrow\left(x-2020\right)\left(\frac{1}{2017}-\frac{1}{2018}-\frac{1}{2}-\frac{1}{3}\right)=0\)

\(\Leftrightarrow x-2020=0\Leftrightarrow x=2020\)

9 tháng 2 2020

\(\frac{x-3}{2017}+\frac{x-2}{2018}=\frac{x-2018}{2}+\frac{x-2017}{3}\\\Leftrightarrow \left(\frac{x-3}{2017}-1\right)+\left(\frac{x-2}{2018}-1\right)=\left(\frac{x-2018}{2}-1\right)+\left(\frac{x-2017}{3}-1\right)\\\Leftrightarrow \frac{x-2020}{2017}+\frac{x-2020}{2018}=\frac{x-2020}{2}+\frac{x-2020}{3}\\ \Leftrightarrow\frac{x-2020}{2017}+\frac{x-2020}{2018}-\frac{x-2020}{2}-\frac{x-2020}{3}=0\\ \Leftrightarrow\left(x-2020\right)\left(\frac{1}{2017}+\frac{1}{2018}-\frac{1}{2}-\frac{1}{3}\right)=0\\ \Leftrightarrow x-2020=0\left(Vi\frac{1}{2017}+\frac{1}{2018}-\frac{1}{2}-\frac{1}{3}\ne0\right)\\ \Leftrightarrow x=2020\)

Vậy tập nghiệm của phương trình trên là \(S=\left\{2020\right\}\)

15 tháng 5 2020

\(\frac{x-3}{2017}+\frac{x-2}{2018}=\frac{x-2018}{2}+\frac{x-2017}{3}\)

\(\Leftrightarrow\) \(\frac{x-3}{2017}-1+\frac{x-2}{2018}-1=\frac{x-2018}{2}-1+\frac{x-2017}{3}-1\)

\(\Leftrightarrow\) \(\frac{x-2020}{2017}+\frac{x-2020}{2018}=\frac{x-2020}{2}+\frac{x-2020}{3}\)

\(\Leftrightarrow\) \(\frac{x-2020}{2017}+\frac{x-2020}{2018}-\frac{x-2020}{2}-\frac{x-2020}{3}=0\)

\(\Leftrightarrow\) (x - 2020)(\(\frac{1}{2017}+\frac{1}{2018}-\frac{1}{2}-\frac{1}{3}\)) = 0

\(\Leftrightarrow\) x - 2020 = 0

\(\Leftrightarrow\) x = 2020

Vậy S = {2020}

Chúc bn học tốt!!

7 tháng 8 2018

help me

7 tháng 8 2018

\(a)\) Ta có : 

\(VP=\frac{2018}{1}+\frac{2017}{2}+\frac{2016}{3}+...+\frac{2}{2017}+\frac{1}{2018}\)

\(VP=\left(\frac{2018}{1}-1-...-1\right)+\left(\frac{2017}{2}+1\right)+\left(\frac{2016}{3}+1\right)+...+\left(\frac{2}{2017}+1\right)+\left(\frac{1}{2018}+1\right)\)

\(VP=1+\frac{2019}{2}+\frac{2019}{3}+...+\frac{2019}{2017}+\frac{2019}{2018}\)

\(VP=2019\left(\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2017}+\frac{1}{2018}+\frac{1}{2019}\right)\)

Lại có : 

\(VT=\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2019}\right).x\)

\(\Rightarrow\)\(x=2019\)

Vậy \(x=2019\)

Chúc bạn học tốt ~ 

a) \(\frac{x+2015}{5}+\frac{x+2016}{4}=\frac{x+2017}{3}+\frac{x+2018}{2}\)

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

\(\Leftrightarrow\frac{x+2020}{5}+\frac{x+2020}{4}=\frac{x+2020}{3}+\frac{x+2002}{2}\)

\(\frac{x+2020}{5}+\frac{x+2020}{4}-\frac{x+2020}{3}-\frac{x+2020}{2}=0\)

\(\Leftrightarrow\left(x+2020\right).\left(\frac{1}{5}+\frac{1}{4}-\frac{1}{3}-\frac{1}{2}\right)=0\)

\(\Leftrightarrow x+2020=0\)

\(\Leftrightarrow x=-2020\)

Vậy : \(x=-2020\)

Chúc bạn học tốt !!

13 tháng 8 2019

a) \(\frac{x+2015}{5}+\frac{x+2016}{4}=\frac{x+2017}{3}+\frac{x+2018}{2}\\ \left(\frac{x+2015}{5}+1\right)+\left(\frac{x+2016}{4}+1\right)=\left(\frac{x+2017}{3}+1\right)+\left(\frac{x+2018}{2}+1\right)\\ \frac{x+2020}{5}+\frac{x+2020}{4}=\frac{x+2020}{3}+\frac{x+2020}{2}\\ \frac{x+2020}{5}+\frac{x+2020}{4}-\frac{x+2020}{3}-\frac{x+2020}{2}=0\\ \left(x+2020\right)\left(\frac{1}{5}+\frac{1}{4}-\frac{1}{3}-\frac{1}{2}\right)=0\\ \Rightarrow x+2020=0\\ \Rightarrow x=-2020\)

Vậy x = -2020

b) \(\frac{x+2015}{5}+\frac{x+2016}{6}=\frac{x+2017}{7}+\frac{x+2018}{8}\\ \left(\frac{x+2015}{5}-1\right)+\left(\frac{x+2016}{6}-1\right)=\left(\frac{x+2017}{7}-1\right)+\left(\frac{x+2018}{8}-1\right)\\ \frac{x+2010}{5}+\frac{x+2010}{6}=\frac{x+2010}{7}+\frac{x+2010}{8}\\ \frac{x+2010}{5}+\frac{x+2010}{6}-\frac{x+2010}{7}-\frac{x+2010}{8}=0\\ \left(x+2010\right)\left(\frac{1}{5}+\frac{1}{6}-\frac{1}{7}-\frac{1}{8}\right)=0\\ \Rightarrow x+2010=0\\ \Rightarrow x=-2010\)

Vậy x = -2010

12 tháng 5 2018

\(\frac{1}{1.3}+\frac{1}{3.5}+...+\frac{1}{x.\left(x+2\right)}=\frac{20}{41}\)

\(\Leftrightarrow\frac{1}{2}.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{x}-\frac{1}{x+2}\right)=\frac{20}{41}\)

\(\Leftrightarrow\frac{1}{2}.\left(1-\frac{1}{x+2}\right)=\frac{20}{41}\)

\(\Leftrightarrow1-\frac{1}{x+2}=\frac{20}{41}\div\frac{1}{2}\)

\(\Leftrightarrow1-\frac{1}{x+2}=\frac{40}{41}\)

\(\Leftrightarrow\frac{1}{x+2}=1-\frac{40}{41}\)

\(\Leftrightarrow\frac{1}{x+2}=\frac{1}{41}\)

\(\Leftrightarrow x+2=41\)

\(\Leftrightarrow x=41-2\)

\(\Leftrightarrow x=39\)

5 tháng 4 2020

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22 tháng 4 2019

Sửa đề: \(\frac{x-3}{2018}\rightarrow\frac{x-3}{2016}\)

\(\frac{x-1}{2018}+\frac{x-2}{2017}=\frac{x-3}{2016}+\frac{x-4}{2015}\)

\(\Leftrightarrow\frac{x-1}{2018}-1+\frac{x-2}{2017}-1=\frac{x-3}{2016}-1+\frac{x-4}{2015}-1\)

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

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

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

\(\Leftrightarrow x-2019=0\) (Vì \(\left(\frac{1}{2018}+\frac{1}{2017}-\frac{1}{2016}-\frac{1}{2015}\right)\ne0\) )

\(\Leftrightarrow x=2019\)

Vậy \(S=\left\{2019\right\}\)

18 tháng 8 2019

Này Thục Trinh, chỗ mà \(\frac{x-1}{2018}-1+\frac{x-2}{2017}-1=\frac{x-3}{2016}-1+\frac{x-4}{2015}-1\)

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