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16 tháng 3

\(\dfrac{7}{8}\) : \(x\) + \(\dfrac{3}{4}\) = - \(\dfrac{1}{2}\)

\(\dfrac{7}{8}\) : \(x\)         = - \(\dfrac{1}{2}\) - \(\dfrac{3}{4}\)

\(\dfrac{7}{8}\) : \(x\)       = - \(\dfrac{5}{4}\)

\(x\) = \(\dfrac{7}{8}\) : (- \(\dfrac{5}{4}\))

\(x\) = - \(\dfrac{7}{10}\)

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

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

9 tháng 12 2019

Ko chép đề

\(2)x-17+x=x-7\)

\(x+x-x=-7+17\)

\(x=-10\)

Vậy ....

5 tháng 8 2021

âm 10 , nhỉ ?

18 tháng 4 2023

\(1,-\dfrac{4}{7}+\dfrac{2}{3}\times\dfrac{-9}{14}\)

\(=\dfrac{-4}{7}+\dfrac{-18}{42}\)

\(=\dfrac{-4\times6}{7\times6}+\dfrac{-18}{42}\)

\(=\dfrac{-20}{42}+\dfrac{-18}{42}\)

\(=-\dfrac{38}{42}\)

\(=-\dfrac{19}{21}\)

\(2,\dfrac{17}{13}-\left(\dfrac{4}{13}-11\right)\)

\(=\dfrac{17}{13}-\dfrac{4}{13}+11\)

\(=\dfrac{13}{13}+11\)

\(=1+11\)

\(=12\)

\(3,8\dfrac{2}{7}-\left(3\dfrac{4}{9}+4\dfrac{2}{7}\right)\)

\(=\dfrac{58}{7}-\left(\dfrac{31}{9}+\dfrac{30}{7}\right)\)

\(=\dfrac{58}{7}-\dfrac{31}{9}-\dfrac{30}{7}\)

\(=\dfrac{58}{7}-\dfrac{30}{7}-\dfrac{31}{9}\)

\(=\dfrac{28}{7}-\dfrac{31}{9}\)

\(=\dfrac{28\times9}{7\times9}-\dfrac{31\times7}{9\times7}\)

\(=\dfrac{252}{63}-\dfrac{217}{63}\)

\(=\dfrac{35}{63}\)

\(=\dfrac{5}{9}\)

\(5,\left(\dfrac{2}{3}-1\dfrac{1}{2}\right):\dfrac{4}{3}+\dfrac{1}{2}\)

\(=\left(\dfrac{2}{3}-\dfrac{3}{2}\right):\dfrac{4}{3}+\dfrac{1}{2}\)

\(=\left(\dfrac{2\times2}{3\times2}-\dfrac{3\times3}{2\times3}\right):\dfrac{4}{3}+\dfrac{1}{2}\)

\(=\left(\dfrac{4}{6}-\dfrac{9}{6}\right):\dfrac{4}{3}+\dfrac{1}{2}\)

\(=\dfrac{-5}{6}:\dfrac{4}{3}+\dfrac{1}{2}\)

\(=\dfrac{-5}{6}\times\dfrac{3}{4}+\dfrac{1}{2}\)

\(=\dfrac{-15}{24}+\dfrac{1}{2}\)

\(=\dfrac{-15}{24}+\dfrac{1\times12}{2\times12}\)

\(=\dfrac{-15}{24}+\dfrac{12}{24}\)

\(=\dfrac{-3}{24}\)

\(=-\dfrac{1}{8}\)

\(6,\dfrac{-5}{13}+\dfrac{2}{5}+\dfrac{-8}{13}+\dfrac{3}{5}-\dfrac{3}{7}\)

\(=\left(\dfrac{-5}{13}+\dfrac{-8}{13}\right)+\left(\dfrac{2}{5}+\dfrac{3}{5}\right)-\dfrac{3}{7}\)

\(=\dfrac{-13}{13}+\dfrac{5}{5}-\dfrac{3}{7}\)

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

\(=-\dfrac{3}{7}\)

\(7,\dfrac{6}{5}\times\dfrac{3}{7}+\dfrac{6}{5}:\dfrac{7}{10}+\dfrac{6}{5}\)

\(=\dfrac{6}{5}\times\dfrac{3}{7}+\dfrac{6}{5}\times\dfrac{10}{7}+\dfrac{6}{5}\)

\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+1\right)\)

\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+\dfrac{1\times7}{1\times7}\right)\)

\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+\dfrac{7}{7}\right)\)

\(=\dfrac{6}{5}\times\dfrac{20}{7}\)

\(=\dfrac{120}{35}\)

\(=\dfrac{24}{7}\)

 

29 tháng 8

Bài 1: Tìm \(x\) 

a; \(x-2\) + 7 = 1.3.(-9)

   \(x\) - 2 + 7 = 3.(-9)

   \(x\) - 2 + 7 = - 27

  \(x\)             = - 27 - 7 + 2

   \(x\)            = - 34 + 2

   \(x\)            = - 32

Vậy \(x=-32\)

29 tháng 8

Bài 1

c; - 2\(x\) + 5 = 7

     - 2\(x\)       = 7  - 5

    - 2\(x\)        = - 2

        \(x\)        = -2 : (-2)

        \(x\)        = - 1

Vậy \(x\)         = - 1

 

3: 

\(=\dfrac{1}{7}\cdot\dfrac{3}{5}\cdot\dfrac{5}{6}\cdot\dfrac{5}{8}=\dfrac{1}{7}\cdot\dfrac{1}{2}\cdot\dfrac{5}{8}=\dfrac{5}{112}\)

4:

=>2/3:x=-2-1/3=-7/3

=>x=-2/3:7/3=-2/7

5:

AC=CB=12/2=6cm

IB=6/2=3cm

21 tháng 4 2019

Câu 1 :

a, 8.( -5 ).( -4 ).2

= [ 8.2 ].[( -5 ).(-4 ]

= 16.20

= 320

b, \(1\frac{3}{7}+\frac{-1}{3}+2\frac{4}{7}\)

\(=\frac{10}{7}+\frac{-1}{3}+\frac{18}{7}\)

\(=\frac{11}{3}\)

c, \(\frac{8}{5}.\frac{2}{3}+\frac{-5.5}{3.5}\)

\(=\frac{8}{3}+\frac{-5}{3}\)

\(=\frac{3}{3}=1\)

d, \(\frac{6}{7}+\frac{5}{8}:5-\frac{3}{16}.\left(-2\right)^2\)

\(=\frac{6}{7}+\frac{1}{8}-\frac{3}{16}.4\)

\(=\frac{55}{56}-\frac{3}{4}\)

\(=\frac{13}{56}\)

21 tháng 4 2019

Câu 2 :

a, 2x + 10 = 16

    2x = 16 + 10

    2x = 26

    x = 26 : 2

    x = 13

b, \(x-\frac{1}{3}=\frac{5}{4}\)

\(x=\frac{5}{4}+\frac{1}{3}\)

\(x=\frac{19}{12}\)

c, \(2x+3\frac{1}{3}=7\frac{1}{3}\)

\(2x+\frac{10}{3}=\frac{22}{3}\)

\(2x=\frac{22}{3}-\frac{10}{3}\)

\(2x=4\)

\(x=4:2\)

\(x=2\)

d, \(\left(\frac{2}{11}+\frac{1}{3}\right)x=\left(\frac{1}{7}-\frac{1}{8}\right).56\)

\(\frac{17}{33}x=1\)

\(x=1-\frac{17}{33}\)

\(x=\frac{16}{33}\)

7 tháng 3 2018

Phan k hai kho tho dau bai : Dem nay bac khong ngu

7 tháng 3 2018

ko hiểu phan nhưng bài đêm nay bác ko ngủ mk học qua r

\(\text{-7129+1478+7129+(-1479)}\)

\(=\text{-7129+7129+1478+(-1479)}\)

\(=0-1=-1\)

\(\text{|-5|.(-7)+4.(-9)}\)

\(=\text{5.(-7)+4.(-9)}\)

\(=\left(-35\right)+\left(-36\right)=-71\)