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24 tháng 9 2020

Ơ,thế đề bài là \(4-\frac{1}{3}=x\) à?

\(4-\frac{1}{3}=\frac{4\times3-1}{3}=\frac{11}{3}\)

24 tháng 9 2020

\(\frac{4}{5}+\frac{1}{6}-\frac{4}{9}=\frac{29}{30}-\frac{4}{9}=\frac{87}{90}-\frac{40}{90}=\frac{11}{30}\)

\(\frac{2}{3}-\frac{1}{4}=\frac{8}{12}-\frac{3}{12}=\frac{5}{12}\)

\(\frac{5}{12}=\frac{150}{360};\frac{11}{30}=\frac{132}{360}\)

\(x=\frac{19}{360}\)

Bài 2: 

a) Ta có: \(\left|x-2\right|=\left|4-x\right|\)

\(\Leftrightarrow x-2=4-x\)

\(\Leftrightarrow2x=6\)

hay x=3

b) Ta có: \(\left(\left|2x-1\right|-3\right)\cdot\left(-2\right)+\left(-5\right)=6\)

\(\Leftrightarrow\left(\left|2x-1\right|-3\right)\cdot\left(-2\right)=11\)

\(\Leftrightarrow\left|2x-1\right|-3=\dfrac{-11}{2}\)

\(\Leftrightarrow\left|2x-1\right|=\dfrac{-11}{2}+\dfrac{6}{2}=\dfrac{-5}{2}\)(Vô lý)

6 tháng 8 2021

thx

17 tháng 7 2023

\(\left(x-\dfrac{4}{7}\right):-\dfrac{1}{3}=1\)
\(\Rightarrow x-\dfrac{4}{7}=1\cdot-\dfrac{1}{3}\)

\(\Rightarrow x-\dfrac{4}{7}=-\dfrac{1}{3}\)

\(\Rightarrow x=-\dfrac{1}{3}+\dfrac{4}{7}\)

\(\Rightarrow x=\dfrac{5}{12}\)

___________________

\(\dfrac{2}{3}-\dfrac{7}{4}:x=\dfrac{5}{6}\)

\(\Rightarrow\dfrac{7}{4}:x=\dfrac{2}{3}-\dfrac{5}{6}\)

\(\Rightarrow\dfrac{7}{4}:x=-\dfrac{1}{6}\)

\(\Rightarrow x=\dfrac{7}{4}:-\dfrac{1}{6}\)

\(\Rightarrow x=-\dfrac{21}{2}\)

17 tháng 7 2023

(x - 4/7) : (-1/3) = 1

x - 4/7 = -1/3

x = -1/3 +4/7

x = 5/21

--------------------

2/3 + 7/4 : x = 5/6

7/4 : x = 5/6 - 2/3

7/4 : x = 1/6

x = 7/4 : 1/6

x = 21/2

11 tháng 10 2017

\(\left(\frac{1}{7}x-\frac{2}{7}\right)\left(\frac{1}{5}x+\frac{3}{5}\right)\left(\frac{1}{3}x+\frac{4}{3}\right)=0\)

<=> \(\frac{x-2}{7}.\frac{x+3}{5}.\frac{x+4}{3}=0\)

<=> \(\frac{x-2}{7}=0\)hoặc \(\frac{x+3}{5}=0\)\(\frac{x+4}{3}=0\)

Nếu \(\frac{x-2}{7}=0\)<=> \(x-2=0\)<=> \(x=2\)
Nếu \(\frac{x+3}{5}=0\)<=> \(x+3=0\) <=> \(x=3\)

Nếu \(\frac{x+4}{3}=0\)<=> \(x+4=0\)<=> \(x=4\)

Vây x= 2 hoặc 3; 4

28 tháng 9 2017

x^2=16

Suy ra x^2=4^2

Vậy x^2=4^2

5 tháng 10 2017

[1/(x+2)-1/(x+5)]+[1/(x+5)-1/(x+10)]+[1/(x+10)-1/(x+17)]=x/15.[1/(x+2)-1/(x+17)]
1/(x+2)-1/(x+17)=x/15.[1/(x+2)-1/(x+17)]
1=x/15
x=15

16 tháng 6 2016

*\(\frac{\left(\frac{3}{10}-\frac{4}{15}-\frac{7}{20}\right).\frac{5}{19}}{\left[\frac{1}{14}+\frac{1}{7}-\left(-\frac{3}{35}\right)\right].\frac{4}{3}}=\frac{\left(\frac{18}{60}-\frac{16}{60}-\frac{21}{60}\right).\frac{5}{19}}{\left(\frac{5}{70}+\frac{10}{70}+\frac{6}{70}\right).\frac{4}{3}}=\frac{\frac{-19}{60}.\frac{5}{19}}{\frac{21}{70}.\frac{4}{3}}=\frac{\frac{-1}{12}}{\frac{14}{35}}=-\frac{1}{12}.\frac{35}{14}=\frac{-35}{168}\)

*\(\frac{\left(1+2+3+...+100\right).\left(\frac{1}{3}-\frac{1}{5}-\frac{1}{7}-\frac{1}{9}\right).\left(6,3.12-21.3,6\right)}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)

=\(\frac{\left(1+2+3+...+100\right)\left(\frac{1}{3}-\frac{1}{5}-\frac{1}{7}-\frac{1}{9}\right).\left(\frac{63}{10}.12-21.\frac{18}{5}\right)}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)

=\(\frac{\left(1+2+3+...+100\right)\left(\frac{1}{3}-\frac{1}{5}-\frac{1}{7}-\frac{1}{9}\right).\left(\frac{378}{5}-\frac{378}{5}\right)}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)

=\(\frac{\left(1+2+3+...+100\right)\left(\frac{1}{3}-\frac{1}{5}-\frac{1}{7}-\frac{1}{9}\right).0}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}=0\)