a) y = 5/14 : 6/7

y = 5/12 

vậy y = 5/12

b) y = 4/9 x 2/3 

y = 8/27 

vậy t = 8/27

c) y = 1/2 - 3/10 

y = 1/5

vậy y = 1/5

d) y = 5/6 - 1/3

y = 1/2

vậy y = 1/2

a) \(\frac{7}{10}-y\cdot\frac{3}{4}=\frac{1}{5}\)

\(y\cdot\frac{3}{4}=\frac{7}{10}-\frac{1}{5}\)

\(y\cdot\frac{3}{4}=\frac{1}{2}\)

\(y=\frac{1}{2}:\frac{3}{4}\)

\(y=\frac{1}{2}\cdot\frac{4}{3}\)

\(y=\frac{2}{3}\)

b) \(\frac{5}{6}:\left(y+\frac{7}{9}\right)=\frac{3}{4}\)

\(y+\frac{7}{9}=\frac{5}{6}:\frac{3}{4}\)

\(y+\frac{7}{9}=\frac{5}{6}\cdot\frac{4}{3}\)

\(y+\frac{7}{9}=\frac{10}{9}\)

\(y=\frac{10}{9}-\frac{7}{9}\)

\(y=\frac{3}{9}=\frac{1}{3}\)

**** !

a, \(\frac{7}{10}-y\times\frac{3}{4}=\frac{1}{5}\)

\(\Rightarrow y\times\frac{3}{4}=\frac{7}{10}-\frac{1}{5}\)

\(\Rightarrow y\times\frac{3}{4}=\frac{1}{2}\)

\(\Rightarrow y=\frac{1}{2}\div\frac{3}{4}\)

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

b, \(\frac{5}{6}\div\left(y+\frac{7}{9}\right)=\frac{3}{4}\)

\(\Rightarrow y+\frac{7}{9}=\frac{5}{6}\div\frac{3}{4}\)

\(\Rightarrow y+\frac{7}{9}=\frac{10}{9}\)

\(\Rightarrow y=\frac{10}{9}-\frac{7}{9}\)

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

a) 7/10 - y × 3/4 = 1/5

                y × 3/4 = 7/10 - 1/5

                y × 3/4 = 1/2

                          y = 1/2 : 3/4

                          y = 2/3. Vậy y = 2/3

b) 5/6 : ( y + 7/9 ) = 3/4

                  y + 7/9 = 5/6 : 3/4

                  y + 7/9 = 10/9

                            y. = 10/9 - 7/9

                            y = 1/3. Vậy y = 1/3

\(\frac{7}{10}\)- y * \(\frac{3}{4}\)= \(\frac{1}{5}\)

y * \(\frac{3}{4}\)= \(\frac{7}{10}\)- \(\frac{1}{5}\)

y * \(\frac{3}{4}\)= \(\frac{1}{2}\)

y = \(\frac{1}{2}\): \(\frac{3}{4}\)

y = \(\frac{2}{3}\)

Vậy y = \(\frac{2}{3}\)

\(\frac{5}{6}\): ( y + \(\frac{7}{9}\)) = \(\frac{3}{4}\)

y + \(\frac{7}{9}\) = \(\frac{5}{6}\): \(\frac{3}{4}\)

y + \(\frac{7}{9}\) = \(\frac{10}{9}\)

y = \(\frac{10}{9}\)- \(\frac{7}{9}\)

y = \(\frac{3}{9}\)

Vậy y = \(\frac{3}{9}\)

a, \(\frac{7}{10}\)- y x \(\frac{3}{4}\)= \(\frac{1}{5}\)

\(\frac{7}{10}\)- y            =  \(\frac{1}{5}\): \(\frac{3}{4}\)

\(\frac{7}{10}\)- y            = \(\frac{4}{15}\)

 y                       = \(\frac{7}{10}\)-  \(\frac{4}{15}\)

y                        = \(\frac{13}{30}\)

b, \(\frac{5}{6}\): ( y + \(\frac{7}{9}\)) = \(\frac{3}{4}\)

                y + \(\frac{7}{9}\)= \(\frac{5}{6}\): \(\frac{3}{4}\)

                y + \(\frac{7}{9}\)= \(\frac{10}{9}\)

                y             = \(\frac{10}{9}\)- \(\frac{7}{9}\)

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

a)y=5/6

b)y=11/4

\(a\left(\frac{1}{2}-\frac{1}{4}+....+\frac{1}{8}-\frac{1}{10}\right).y=\frac{1}{3}\)
\(\left(\frac{1}{2}-\frac{1}{10}\right).y=\frac{1}{3}\)

\(\frac{2}{5}.y=\frac{1}{3}\)

      \(y=\frac{1}{3}:\frac{2}{5}\)

     \(y=\frac{5}{6}\)

\(b,\left(\frac{1}{1}-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+....+\frac{1}{9}-\frac{1}{11}\right).y=\frac{2}{3}\)

     \(\left(\frac{1}{1}-\frac{1}{11}\right).y=\frac{2}{3}\)

      \(\frac{10}{11}.y=\frac{2}{3}\)

              \(y=\frac{2}{3}:\frac{10}{11}\)

               \(y=\frac{22}{30}\)

\(\frac{7}{y}=\frac{1}{12}\)

\(=>\frac{7}{y}=\frac{7}{84}\)

\(=>y=84\)

\(\frac{9}{10}-y.\frac{3}{4}=\frac{2}{5}\)

\(y.\frac{3}{4}=\frac{9}{10}-\frac{2}{5}=\frac{1}{2}\)

\(y=\frac{1}{2}:\frac{3}{4}\)

\(y=\frac{1}{2}.\frac{4}{3}\)

\(y=\frac{2}{3}\)

\(\frac{5}{6}:\left[y+\frac{7}{9}\right]=\frac{3}{4}\)

\(y+\frac{7}{9}=\frac{5}{6}:\frac{3}{4}\)

\(y+\frac{7}{9}=\frac{5}{6}.\frac{4}{3}\)

\(y+\frac{7}{9}=\frac{10}{9}\)

\(y=\frac{10}{9}-\frac{7}{9}\)

\(y=\frac{3}{9}\)

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

1,   7/y=1/12

=>7.12=y

=>y=84

2,  9/10-y.3/4=2/5

=>y.3/4=9/10-2/5

=>y.3/4=1/2

=>y=1/2:3/4=2/3

3, 5/6[y+7/9]=3/4

 =>y+7/9=5/6:3/4

=>y+7/9=10/9

=>y=10/9-7/9

=>y=1/3

Tìm y:

a)7/y=1/12

   7x12=1xy

       84=1xy

      1xy=84

          y=84:1

          y=84

b)9/10-y*3/4=2/5

           y*3/4=9/10-2/5

           y*3/4=9/10-4/10

           y*3/4=5/10

           y*3/4=1/2

                  y=1/2:3/4

                  y=1/2*4/3

                  y=1*2/1*3

                  y=2/3

c)5/6:[y+7/9]=3/4

          y+7/9 =5/6:3/4

          y+7/9 =5/6x4/3

          y+7/9 =5x2/3x3

          y+7/9 =10/9

                  y=10/9-7/9

                  y=3/9

E = x^(4)*y^(4)+x^(5)*y^(5)+x^(6)*y^(6)+x^(7)*y^(7)+x^(8)*y^(8)+x^(9)*y^(9)+x^(10)*y^(10) tại x=-1, y=1 nha

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Bài 2: 

a: 2/5=14/35

3/7=15/35

b: -3/4=-9/12

-7/-12=7/12

c: 5/9=60/108

-11/-12=11/12=99/108

d: -4/7=-36/63

8/9=56/63

-10/21=-30/63

Bài 2: 

a: 2/5=14/35

3/7=15/35

b: -3/4=-9/12

-7/-12=7/12

c: 5/9=60/108

-11/-12=11/12=99/108

d: -4/7=-36/63

8/9=56/63

-10/21=-30/63

cho mik đi r mik giúp cho

a.

x/y x 3/4 = 5/6 + 1/3

x/y x 3/4 = 7/6

        x/y = 7/6 : 3/4 

        x/y = 14/9

b.

7/9 : x/y = 10/7 - 13/14

7/9 : x/y = 1/2

        x/y = 7/9 : 1/2

        x/y = 14/9

cho 1 k nha bn

X/y = 14/9

Nha 

Ht