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1 tháng 5 2019

ko bit :D

18 tháng 4 2018

a) \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}.\frac{64}{49}\)

\(\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)

\(\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)

\(\frac{x}{2}=\frac{117}{35}\)

\(x=\frac{117}{35}\times2\)

\(x=\frac{234}{35}\)

b) \(\frac{y}{5}+\frac{9}{2}=\frac{6}{7}.\frac{36}{49}\)

\(\frac{y}{5}+\frac{9}{2}=\frac{216}{343}\)

\(\frac{y}{5}=\frac{216}{343}-\frac{9}{2}\)

\(\frac{y}{5}=\frac{-2655}{686}\)

\(y=\frac{-2655}{686}.5\)

\(y=\frac{-13275}{686}\)

ra kết quả to quá bn ạ! Bn xem lại giúp mk nha!

6 tháng 12 2016

may cai bai day ma cung khong biet oc cho

6 tháng 12 2016

a) 89-(73-x)=20

=>73-x=89-20

=>73-x=69

=>x=73-69

=>x=4

4 tháng 1 2019

a) 89-(73-x) = 20

=> 73+x =89-20

=> 73+x=69

=> x=69-73

=> x=-4

b) (x+7)-25=13

=> x+7=13+25

=> x+7=38

=> x=38-7

=> x=31

c) 98-(x+4)=20

=> x+4=98-20

=> x+4=78

=> x=78-4

=> x=73

4 tháng 1 2019

d) 140:(x-8)=7

=> x-8=140:7

=> x-8=20

=> x=20+8

=> x=28

e) 4(x+41)=400

=> x+41=400:4

=> x+41=100

=> x=100-41

=> x=59

f) x-[42+(-28)]=-8

=> x-14=-8

=> x=-8+14

=> x=6

1 tháng 5 2017

a) \(\frac{X}{2}-\frac{11}{5}=\frac{7}{8}\cdot\frac{64}{49}\)

\(\Rightarrow\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)

\(\Rightarrow\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)

\(\Rightarrow\frac{x}{2}=\frac{117}{35}\)\(\Rightarrow x=\frac{117}{35}\cdot2=\frac{234}{35}\)

b)\(\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\cdot\frac{36}{49}\)

\(\Rightarrow\frac{x}{5}+\frac{9}{2}=\frac{216}{343}\)

\(\Rightarrow\frac{x}{5}=\frac{216}{343}-\frac{9}{2}=\frac{-2655}{686}\)

\(\Rightarrow x=\frac{-2655}{686}\cdot5=\frac{-13275}{686}\)

1 tháng 5 2017

        x/2 - 11/5 = 7/8 . 64/49

        x/2 - 11/5 = 8/7

        x/2          =8/7 + 11/5

        x/2          = 117/35

        x             = 2.117/35 ( tính chất phân số bằng nhau)

        x             = 234/35 

       x/5 + 9/2 = 6/7 . 36/49

       x/5 + 9/2 = 216/343

        x/5         = 216/343 - 9/2

        x/5         = -2655/686

        x           = 5.(-2655)/686

        x           = -13275/686 

Bài 1:

a: \(x=\dfrac{2}{3}:\dfrac{3}{5}=\dfrac{2}{3}\cdot\dfrac{5}{3}=\dfrac{10}{9}\)

b: \(x=\dfrac{17}{8}:\dfrac{7}{17}=\dfrac{17}{8}\cdot\dfrac{17}{7}=\dfrac{289}{56}\)

c: \(x=-\dfrac{3}{4}:\dfrac{7}{12}=\dfrac{-3}{4}\cdot\dfrac{12}{7}=\dfrac{-63}{28}=-\dfrac{9}{4}\)

d: \(\Leftrightarrow x\cdot\dfrac{1}{6}=\dfrac{3}{8}-\dfrac{1}{4}=\dfrac{1}{4}\)

hay \(x=\dfrac{1}{4}:\dfrac{1}{6}=\dfrac{3}{2}\)

e: \(\Leftrightarrow\dfrac{1}{2}:x=-4-\dfrac{1}{3}=-\dfrac{17}{3}\)

hay \(x=-\dfrac{1}{2}:\dfrac{17}{3}=\dfrac{-3}{34}\)

27 tháng 7 2023

dad

2: \(=\dfrac{-2}{75}+\dfrac{5}{39}=\dfrac{33}{325}\)

3: \(=\dfrac{6}{11}\left(\dfrac{4}{9}+\dfrac{5}{9}\right)=\dfrac{6}{11}\)

4: \(=\dfrac{7}{19}\left(\dfrac{5}{13}+\dfrac{8}{13}-1\right)=-2\cdot\dfrac{7}{19}=-\dfrac{14}{19}\)

5: \(=\dfrac{2}{7}\left(\dfrac{4}{23}-\dfrac{27}{23}+1\right)=0\)

6: \(=\dfrac{3}{8}\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\dfrac{11}{8}=\dfrac{3}{8}+\dfrac{11}{8}=\dfrac{14}{8}=\dfrac{7}{4}\)

19 tháng 1 2018

Câu b bài 1 hình như là sai đề rồi e tề

2 tháng 6 2017

a) \(\dfrac{2}{3}x-\dfrac{1}{2}=\dfrac{1}{10}\)

\(\dfrac{2}{3}x=\dfrac{1}{10}+\dfrac{1}{2}=\dfrac{3}{5}\)

\(x=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{9}{10}\)

b) \(\dfrac{39}{7}:x=13\)

\(x=\dfrac{\dfrac{39}{7}}{13}=\dfrac{3}{7}\)

c) \(\left(\dfrac{14}{5}x-50\right):\dfrac{2}{3}=51\)

\(\dfrac{14}{5}x-50=51\cdot\dfrac{2}{3}=34\)

\(\dfrac{14}{5}x=34+50=84\)

\(x=\dfrac{84}{\dfrac{14}{5}}=30\)

d) \(\left(x+\dfrac{1}{2}\right)\left(\dfrac{2}{3}-2x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)

e) \(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{12}\)

\(\dfrac{1}{6}x=\dfrac{5}{12}\)

\(x=\dfrac{5}{12}:\dfrac{1}{6}=\dfrac{5}{2}\)

g) \(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\dfrac{11}{5}-\dfrac{3}{7}=-2\)

\(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)

\(x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{11}{7}:\dfrac{11}{5}=-\dfrac{5}{7}\)

\(\dfrac{44}{7}x=-\dfrac{5}{7}-\dfrac{3}{7}=-\dfrac{8}{7}\)

\(x=-\dfrac{8}{7}:\dfrac{44}{7}=-\dfrac{2}{11}\)

h) \(\dfrac{13}{4}x+\left(-\dfrac{7}{6}\right)x-\dfrac{5}{3}=\dfrac{5}{12}\)

\(\dfrac{25}{12}x-\dfrac{5}{3}=\dfrac{5}{12}\)

\(\dfrac{25}{12}x=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{25}{12}\)

\(x=1\)

Mỏi tay woa bn làm nốt nha!!