<=> (x-18/74 - 1)+(x-20/72 - 1)+(x-22/70 - 1) = 0

<=> x-92/74 + x-92/72 + x-92/70 = 0

<=> (x-92).(1/74+1/72+1/70) = 0

<=> x-92 = 0 ( vì 1/74 + 1/72 + 1/70 > 0 )

<=> x=92

Vậy S = {92}

Tk mk nha

Ta có :

\(\frac{x-18}{74}+\frac{x-20}{72}+\frac{x-22}{70}=3\)

\(\Leftrightarrow\)\(\left(\frac{x-18}{74}-1\right)+\left(\frac{x-20}{72}-1\right)+\left(\frac{x-22}{70}-1\right)=3-3\)

\(\Leftrightarrow\)\(\frac{x-92}{74}+\frac{x-92}{72}+\frac{x-92}{70}=0\)

\(\Leftrightarrow\)\(\left(x-92\right)\left(\frac{1}{74}+\frac{1}{72}+\frac{1}{70}\right)=0\)

Vì \(\left(\frac{1}{74}+\frac{1}{72}+\frac{1}{70}\right)\ne0\)

\(\Rightarrow\)\(x-92=0\)

\(\Rightarrow\)\(x=92\)

Vậy \(x=92\)

Chúc bạn học tốt 

\(\frac{74-x}{26}+\frac{75-x}{25}+\frac{76-x}{24}+\frac{77-x}{23}+\frac{78-x}{22}=-5\)

\(\frac{74-x}{26}+1+\frac{75-x}{25}+1+\frac{76-x}{24}+1+\frac{77-x}{23}+1+\frac{78-x}{22}=-5+5\)

\(\frac{74-x}{26}+\frac{26}{26}+\frac{75-x}{25}+\frac{25}{25}+\frac{76-x}{24}+\frac{24}{24}+\frac{77-x}{23}+\frac{23}{23}+\frac{78-x}{22}+\frac{22}{22}=0\)

\(\frac{100-x}{26}+\frac{100-x}{25}+\frac{100-x}{24}+\frac{100-x}{23}+\frac{100-x}{22}=0\)

\(\left(100-x\right)\left(\frac{1}{26}+\frac{1}{25}+\frac{1}{24}+\frac{1}{23}+\frac{1}{22}\right)=0\)

=>100-x=0    ( \(\left(\frac{1}{26}+\frac{1}{25}+\frac{1}{24}+\frac{1}{23}+\frac{1}{22}\right)\ne0\))

x=100

hahaha

Cộng 1 vào mỗi hạng tử trong vế trái là dc

\(\frac{26-x}{995}\)+2+\(\frac{22-x}{997}\)+\(\frac{18-x}{999}\)+2=\(\frac{12-x}{334}\)+6

\(\frac{2016-x}{995.2}\)+\(\frac{2016-x}{997.2}\)+\(\frac{2016-x}{999.2}\)-\(\frac{2016-x}{334.6}\)=0

(2016-x)(\(\frac{1}{995.2}\)+\(\frac{1}{997.2}\)\(\frac{1}{999.2}\)-\(\frac{1}{334.6}\))=0

Dễ thấy giá trị biểu thức trong ngoặc thứ 2 khác 0

Nên 2016-x=0=>x=2016

Vậy giá trị của x là 2016

Theo đề ta có :

\(\frac{x+3}{20}+\frac{x-15}{21}+\frac{x-35}{22}=66\)

\(\Rightarrow\left(\frac{x}{20}+\frac{3}{20}\right)+\left(\frac{x}{21}-\frac{15}{21}\right)+\left(\frac{x}{22}-\frac{35}{22}\right)=66\)

\(\Rightarrow\frac{x}{20}+\frac{3}{20}+\frac{x}{21}-\frac{5}{7}+\frac{x}{22}-\frac{35}{22}=66\)

\(\Rightarrow\left(\frac{x}{20}+\frac{x}{21}+\frac{x}{22}\right)+\left(\frac{3}{20}-\frac{5}{7}-\frac{35}{22}\right)=66\)

\(\Rightarrow x.\left(\frac{1}{20}+\frac{1}{21}+\frac{1}{22}\right)+\frac{-3319}{1540}=66\)

\(\Rightarrow x.\frac{661}{4620}=66-\frac{-3319}{1540}\)

Tới đây lm đc r chứ nhưng mà hình như Akira Nishihiko , bn viết đề sai hay sao á?

THừa số 6 kìa

Ta có: \(\dfrac{-5}{x}=\dfrac{-y}{8}=\dfrac{-18}{72}\)

\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{-5}{x}=-\dfrac{18}{72}=\dfrac{-1}{4}\\\dfrac{-y}{8}=\dfrac{-18}{72}=\dfrac{-1}{4}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=20\\y=2\end{matrix}\right.\)

Vậy: (x,y)=(20;2)

\(\dfrac{-5}{x}=\dfrac{-y}{8}=\dfrac{-18}{72}\) 

+)\(\dfrac{-5}{x}=\dfrac{-18}{72}\) 

\(\Rightarrow x=\dfrac{-5.72}{-18}=20\) 

+)\(\dfrac{-y}{8}=\dfrac{-18}{72}\) 

\(\Rightarrow-y=\dfrac{-18.8}{72}=-2\) 

\(\Rightarrow y=2\)

x thuộc Z

\(\left(x-2\right):\left(\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+\frac{1}{72}\right)=\frac{16}{9}\)

\(\left(x-2\right):\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\right)=\frac{16}{9}\)

\(\left(x-2\right):\frac{2}{9}=\frac{16}{9}\)

\(x-2=\frac{32}{91}\)

\(x=\frac{32}{91}+2\)

\(x=\frac{212}{91}\)

Giúp mình với các bạn ơi!!!!!!!!!!!!!!!!!!!!!!!!!!!!