Question

tìm y

 

7/y=1/12                9/10-y*3/4=2/5                  5/6:[y +7/9]=3/4

Answer 1

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

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

\(=>y=84\)

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

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

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

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

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

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

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

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

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

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

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

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

Answer 2

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

Answer 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