a.1/4

b.-7/144

c.25/21

d.17/7

e.80/63

f.9/7

a)1/4

b)-7/144

c)-25/21

d)17/7

e)16/63

f)9/7

Tự làm đi, lười thế

a) x= 1/4

b) x= -7/144

c) x= 25/6

d) x=17/7

e) x= 80/63

f) x= -45/14

042557

giúp mk vs xin các bạn 

please

=(((((

a, 3.(2\(x\) + 4) + 198 = (-3)².10

   3.(2\(x\) + 4) + 198 = 90

   3.(2\(x\) + 4) = 90  - 198

    3.(2\(x\) + 4) = - 108

       2\(x\) + 4 = -108 : 3

       2\(x\) + 4  = -36

       2\(x\)       = - 36 - 4

      2\(x\)       = - 40

       \(x\)       = -40 : 2

        \(x\)      = - 20 

b, 2.(\(x\) + 7) -  6  = 18

    2.(\(x\) + 7) = 18 + 6

    2.(\(x\) + 7)  =24

         \(x\) + 7 = 24 : 2

         \(x\) + 7  = 12

           \(x\)       = 12 - 7

             \(x\)     = 5

c, 5.(\(x\) + 5) - 3.(\(x\) - 2) = 5² + 18

    5\(x\) + 25 - 3\(x\) + 6 = 25 + 18

    2\(x\) + 31 = 43

    2\(x\)          = 43 - 31

   2\(x\)        = 12

     \(x\)        = 12 : 2

     \(x\)        = 6

\(a.\)

\(\frac{4}{9}.x=\frac{1}{9}\)

\(\Rightarrow x=\frac{1}{9}:\frac{4}{9}\)

\(\Rightarrow x=\frac{1}{9}.\frac{9}{4}\)

\(\Rightarrow x=\frac{1}{4}\)

Vậy \(x=\frac{1}{4}\)

\(b.\)

\(\frac{7}{18}.x-\frac{2}{3}=\frac{5}{18}\)

\(\Rightarrow\frac{7}{18}.x=\frac{5}{18}+\frac{2}{3}\)

\(\Rightarrow\frac{7}{18}.x=\frac{5}{18}+\frac{12}{18}\)

\(\Rightarrow\frac{7}{18}.x=\frac{17}{18}\)

\(\Rightarrow x=\frac{17}{18}:\frac{7}{18}\)

\(\Rightarrow x=\frac{17}{18}.\frac{18}{7}\)

\(\Rightarrow x=\frac{17}{7}\)

Vậy \(x=\frac{17}{7}\)

\(c.\)

\(x:-\frac{1}{12}=\frac{7}{12}\)

\(\Rightarrow x=\frac{7}{12}.-\frac{1}{12}\)

\(\Rightarrow x=-\frac{7}{144}\)

Vậy \(x=-\frac{7}{144}\)

\(d.\)

\(\frac{4}{9}-\frac{7}{8}.x=-\frac{2}{3}\)

\(\Rightarrow\frac{7}{8}.x=\frac{4}{9}-\left(-\frac{2}{3}\right)\)

\(\Rightarrow\frac{7}{8}.x=\frac{4}{9}+\frac{2}{3}\)

\(\Rightarrow\frac{7}{8}.x=\frac{4}{9}+\frac{6}{9}\)

\(\Rightarrow\frac{7}{8}.x=\frac{10}{9}\)

\(\Rightarrow x=\frac{10}{9}:\frac{7}{8}\)

\(\Rightarrow x=\frac{10}{9}.\frac{8}{7}\)

\(\Rightarrow x=\frac{80}{63}\)

Vây \(x=\frac{80}{63}\)

\(e.\)

\(-\frac{5}{14}:x=-\frac{3}{10}\)

\(\Rightarrow x=-\frac{5}{14}:-\frac{3}{10}\)

\(\Rightarrow x=-\frac{5}{14}.-\frac{10}{3}\)

\(\Rightarrow x=\frac{5}{7}.\frac{5}{3}\)

\(\Rightarrow x=\frac{25}{21}\)

Vậy \(x=\frac{25}{21}\)

\(g.\)

\(\frac{1}{6}+\frac{-5}{7}:x=-\frac{7}{18}\)

\(\Rightarrow-\frac{5}{7}:x=-\frac{7}{18}-\frac{1}{6}\)

\(\Rightarrow-\frac{5}{7}:x=-\frac{7}{18}-\frac{3}{18}\)

\(\Rightarrow-\frac{5}{7}:x=-\frac{10}{18}\)

\(\Rightarrow-\frac{5}{7}:x=-\frac{5}{9}\)

\(\Rightarrow x=-\frac{5}{7}:-\frac{5}{9}\)

\(\Rightarrow x=-\frac{5}{7}.-\frac{9}{5}\)

\(\Rightarrow x=\frac{9}{7}\)

Vậy \(x=\frac{9}{7}\)

\(a,\dfrac{5}{13}\times\dfrac{4}{15}\times13=\dfrac{5\times4\times13}{13\times5\times3}=\dfrac{4}{3}\\ b,\left(\dfrac{3}{7}+\dfrac{5}{2}\right)\times\dfrac{7}{5}=\dfrac{3}{7}\times\dfrac{7}{5}+\dfrac{5}{2}\times\dfrac{7}{5}=\dfrac{3}{5}+\dfrac{7}{2}=\dfrac{6}{10}+\dfrac{35}{10}=\dfrac{41}{10}\\ c,\dfrac{1}{5}\times\dfrac{11}{18}+\dfrac{11}{18}\times\dfrac{3}{5}=\dfrac{11}{18}\times\left(\dfrac{1}{5}+\dfrac{3}{5}\right)=\dfrac{11}{18}\times\dfrac{4}{5}=\dfrac{22}{45}\)

a, 4/3  b, 41/10   c,22/45

a, \(\dfrac{7}{18}x-\dfrac{2}{3}=\dfrac{5}{18}\)

\(\dfrac{7}{18}x=\dfrac{5}{18}+\dfrac{2}{3}\)

\(\dfrac{7}{18}x=\dfrac{17}{18}\)

\(x=\dfrac{17}{18}\div\dfrac{7}{18}\)

\(x=\dfrac{17}{7}\)

a) \(\dfrac{7}{18}\).x-\(\dfrac{2}{3}\)=\(\dfrac{5}{18}\)

\(\dfrac{7}{18}\).x =\(\dfrac{5}{18}\)+\(\dfrac{2}{3}\)

\(\dfrac{7}{18}\).x = \(\dfrac{17}{18}\)

x = \(\dfrac{17}{18}\) :\(\dfrac{7}{18}\)

x =\(\dfrac{17}{7}\)

b)\(\dfrac{4}{9}\) - \(\dfrac{7}{8}\).x =\(\dfrac{-2}{3}\)

\(\dfrac{7}{8}\).x =\(\dfrac{4}{9}\)-\(\dfrac{-2}{3}\)

\(\dfrac{7}{8}\).x =\(\dfrac{10}{9}\)

x =\(\dfrac{10}{9}\) : \(\dfrac{7}{8}\)

x =\(\dfrac{80}{63}\)

c)\(\dfrac{1}{6}\)+\(\dfrac{-5}{7}\): \(\dfrac{-7}{18}\)

\(\dfrac{1}{6}\)+\(\dfrac{90}{49}\)

\(\dfrac{589}{294}\)

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