a, y=9/10

b,y=25/14

a ) y = 9/10

b ) y = 25/14

a) y=9/10

b)y =25/14

\(\left(y-\frac{2}{5}\right):\frac{4}{3}=\frac{3}{8}\)

\(y-\frac{2}{5}=\frac{3}{8}.\frac{4}{3}\)

\(y-\frac{2}{5}=\frac{1}{2}\)

\(y=\frac{1}{2}+\frac{2}{5}\)

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

\(y.\frac{5}{6}=\frac{1}{4}+\frac{1}{3}\)

\(y.\frac{5}{6}=\frac{7}{12}\)

\(y=\frac{7}{12}:\frac{5}{6}\)

\(y=\frac{7}{12}.\frac{6}{5}\)

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

a ) \(\left(y-\frac{2}{5}\right):\frac{4}{3}=\frac{3}{8}\)

   \(\left(y-\frac{2}{5}\right)=\frac{3}{8}\times\frac{4}{3}\)

     \(y-\frac{2}{5}=\frac{1}{2}\)

                 \(y=\frac{1}{2}+\frac{2}{5}\)

                \(y=\frac{5}{10}+\frac{4}{10}\)

                 \(y=\frac{9}{10}\)

 Vậy \(y=\frac{9}{10}\)

b ) \(y\times\frac{5}{6}=\frac{1}{4}+\frac{1}{3}\)

\(y\times\frac{5}{6}=\frac{3}{12}+\frac{4}{12}\)

\(y\times\frac{5}{6}=\frac{7}{12}\)

           \(y=\frac{7}{12}:\frac{5}{6}\)

          \(y=\frac{7}{12}\times\frac{6}{5}\)

        \(y=\frac{7}{10}\)

Vậy \(y=\frac{7}{10}\)

Chúc bạn học tốt !!!

1)

( y - 1/5 ) : 2/3 = 3/4

y - 1/5            = 3/4 x 2/3

y - 1/5            = 1/2

y                   = 1/2 + 1/5

y                   = 7/10.

2)

7/4 - y x 5/6 = 1/2 + 1/3

7/4 - y x 5/6 = 5/6

7/4 - y         = 5/6 : 5/6

7/4 - y         = 1

y                = 7/4 - 1

y                = 3/4

C1 :(y-1/5):2/3=3/4

y-1/5=3/4.2/3

y-15=1/2

y=1/2+15

y=31/2

C2:

7/4-y.5/6=1/2+1/3

7/4-y.5/6=5/6

y.5/6=7/4-5/6

y.5/6=11/12

y=11/12:5/6

y=11/10

c)\(\dfrac{3}{8}\times\dfrac{5}{8}+y=\dfrac{5}{4}\) 

   \(\dfrac{15}{64}+y=\dfrac{5}{4}\) 

           \(y=\dfrac{5}{4}-\dfrac{15}{64}\) 

           \(y=\dfrac{65}{64}\)

d, \(\dfrac{3}{8}+\dfrac{5}{8}\times y=\dfrac{5}{4}\) 

          \(\dfrac{5}{8}\times y=\dfrac{5}{4}-\dfrac{3}{8}\) 

          \(\dfrac{5}{8}\times y=\dfrac{7}{8}\) 

                 \(y=\dfrac{7}{8}:\dfrac{5}{8}\) 

                \(y=\dfrac{7}{5}\)

 a, 3/4 x y = 3/5 + 3/10   

3/4 x y = 9/10

y = 9/10 : 3/4

y = 6/5

b, 3/5 : y = 3/4 - 2/5

3/5 : y = 7/20

y = 3/5 : 7/20 

y = 12/7

 y - 2/5 = 5/8 x 4/5

y- 2/5= 1/2

y = 1/2 + 2/5

y= 9/10

\(\left(y-\frac{4}{5}\right):\frac{4}{5}=\frac{5}{8}\)  => \(y-\frac{4}{5}=\frac{1}{2}\)=> \(y=\frac{13}{10}\)

#Hk_tốt

#Ken'z

\(Y:\dfrac{7}{5}=\dfrac{5}{6}+\dfrac{5}{12}=\dfrac{15}{12}\\ Y=\dfrac{15}{12}\times\dfrac{7}{5}=\dfrac{7}{4}\)

\(y:\dfrac{7}{5}=\dfrac{5}{6}+\dfrac{5}{12}\\ \Leftrightarrow y:\dfrac{7}{5}=\dfrac{5\times2}{6\times2}+\dfrac{5}{12}\\ \Leftrightarrow y:\dfrac{7}{5}=\dfrac{10}{12}+\dfrac{5}{12}\\ \Leftrightarrow y:\dfrac{7}{5}=\dfrac{15}{12}\\ \Leftrightarrow y:\dfrac{7}{5}=\dfrac{5}{4}\\ \Leftrightarrow y=\dfrac{5}{4}\times\dfrac{7}{5}\\ \Leftrightarrow y=\dfrac{7}{4}\)

\(\Rightarrow C\)