a) \(y+\frac{3}{4}=\frac{4}{5}\)

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

\(y=\frac{1}{20}\)

b) \(y-\frac{3}{11}=\frac{9}{22}\)

\(y=\frac{9}{22}-\frac{3}{11}\)

\(y=\frac{3}{22}\)

c) \(\frac{9}{2}-y=\frac{2}{9}\)

\(y=\frac{9}{2}-\frac{2}{9}\)

\(y=\frac{77}{18}\)

a, y + 3/4 = 4/5

            y = 4/5 - 3/4

             y = 1/20

b, y - 3/11 = 9/22

              y = 9/22 + 3/11

              y = 15/22

c, 9/2 - y = 2/9

           y = 9/2 - 2/9

            y = 77/18

ủng hộ nha

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

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

         \(y=\frac{1}{20}\)

Vậy y = 1/20

\(y-\frac{3}{11}=\frac{9}{22}\)

          \(y=\frac{9}{22}+\frac{3}{11}\)

          \(y=\frac{15}{22}\)

Vậy y = 15/22

\(\frac{9}{2}-y=\frac{2}{9}\)

         \(y=\frac{9}{2}-\frac{2}{9}\)

        \(y=\frac{77}{18}\)

Vậy y = 77/18

Cảm ơn Sakura!

Nếu anh không biết thì thôi biết thì giải hộ em bài này

a 1/20

b 15/22

c 77/18

bằng nhau và bằng 5/4

Bài 1              

a) y + 3/4 = 4/5                                         b) y - 3/11 = 9/22                                                  c) 9/2 - y = 2/9

             y = 4/5 - 3/4                                               y = 9/22 + 3/11                                                    y = 9/2 - 2/9

             y = 1/20                                                     y = 15/22                                                             y = 77/18

Vậy y = 1/20                                             Vậy y = 15/22                                                        Vậy y = 77/18

Bài 2

( 9/2 - 5/2 ) - 3/4 = 2 - 3/4 = 5/4

9/2 - ( 5/2 + 3/4 ) = 9/2 - 13/4 = 5/4

Vậy :( 9/2 - 5/2 ) - 3/4 = 9/2 - ( 5/2 + 3/4)

mn. giúp em nha 

\(a.\dfrac{6}{5}=\dfrac{18}{x}\Rightarrow x=\dfrac{18\cdot5}{6}=15\\ \text{Vậy}\text{ }x=15.\)

\(b.\dfrac{3}{4}=\dfrac{-21}{x}\Rightarrow x=\dfrac{-21\cdot4}{3}=28\\ \text{ }\text{ }\text{ }\text{ }\text{Vậy }x=28.\)

\(c.\dfrac{x}{4}=\dfrac{21}{28}\Rightarrow x=\dfrac{21\cdot4}{28}=3\\ \text{Vậy }x=3.\)

\(d.\dfrac{-8}{2x}=\dfrac{3}{-9}\Rightarrow x=\dfrac{-8\cdot\left(-9\right)}{3}:2=12\\ \text{Vậy }x=12.\)

\(e.\dfrac{-4}{11}=\dfrac{x}{22}=\dfrac{40}{z}\\ \Rightarrow x=\dfrac{-4\cdot22}{11}=-8\\ \Rightarrow z=\dfrac{22\cdot40}{-8}=-110\\ \text{Vậy }x=-8;z=-110.\)

\(f.\dfrac{-3}{4}=\dfrac{x}{20}=\dfrac{21}{y}\\ \Rightarrow x=\dfrac{-3\cdot20}{4}=-15\\ \Rightarrow y=\dfrac{21\cdot20}{-15}=-28\\ \text{Vậy }x=-15;y=-28.\)

\(g.\dfrac{-4}{8}=\dfrac{x}{-10}=\dfrac{-7}{y}=\dfrac{z}{-24}\\ \Rightarrow x=\dfrac{-4\cdot\left(-10\right)}{8}=5\\ \Rightarrow y=\dfrac{-7\cdot\left(-10\right)}{5}=14\\ \Rightarrow z=\dfrac{-7\cdot\left(-24\right)}{14}=12\\ \text{Vậy }x=5;y=14;z=12.\)

\(h.\dfrac{x}{4}=\dfrac{9}{x}\\ \Rightarrow x\cdot x=9\cdot4\\ \Rightarrow x\cdot x=36\\ \Rightarrow x\cdot x=6\cdot6\\ \text{Vậy }\text{cả hai }x=6.\)

a, y \(\times\) \(\dfrac{4}{3}\) = \(\dfrac{16}{9}\)

    y         =    \(\dfrac{16}{9}\) : \(\dfrac{4}{3}\)

    y         = \(\dfrac{4}{3}\)

b, ( y - \(\dfrac{1}{2}\)) + 0,5 = \(\dfrac{3}{4}\)

    y - 0,5 + 0,5 = \(\dfrac{3}{4}\)

   y                   = \(\dfrac{3}{4}\)

c, \(\dfrac{4}{5}-\dfrac{2}{5}y\) = 0,2

   0,8 - 0,4y = 0,2

           0,4y = 0,8 - 0,2

           0,4y  = 0,6

               y = 1,5

d, (y + \(\dfrac{3}{4}\)) \(\times\) \(\dfrac{5}{7}\) = \(\dfrac{10}{9}\)

    y + \(\dfrac{3}{4}\)           = \(\dfrac{10}{9}\) : \(\dfrac{5}{7}\)

   y + \(\dfrac{3}{4}\)            = \(\dfrac{14}{9}\)

y                    = \(\dfrac{14}{9}\) - \(\dfrac{3}{4}\)

 y                   =   \(\dfrac{29}{36}\)

e, y : \(\dfrac{5}{4}\)         = \(\dfrac{9}{5}\)  + \(\dfrac{1}{2}\)

   y : \(\dfrac{5}{4}\)         =   \(\dfrac{23}{10}\)

  y                =      \(\dfrac{23}{10}\)

  y               =   \(\dfrac{23}{8}\)

f, y \(\times\) \(\dfrac{1}{2}\) + \(\dfrac{3}{2}\) \(\times\) y   = \(\dfrac{4}{5}\)

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

   2y                       = \(\dfrac{4}{5}\)

    y                        = \(\dfrac{2}{5}\)

\(a,5\frac{1}{4}+3,25-50\%+y=15,25\)

\(\Leftrightarrow5,25+3,25-\frac{50}{100}+y=15,25\)

\(\Leftrightarrow5,25+3,25-0,5+y=15,25\)

\(\Leftrightarrow8+y=15,25\)

\(\Leftrightarrow y=15,25-8=7,25\)

\(b,(y-3):2=2010\)

\(\Leftrightarrow y-3=4020\)

\(\Leftrightarrow y=4023\)

\(c,\frac{7+y}{33}=\frac{9}{11}\)

\(\Leftrightarrow7+y=\frac{9}{11}\cdot33\)

\(\Leftrightarrow7+y=\frac{9}{1}\cdot3\)

\(\Leftrightarrow7+y=27\Leftrightarrow y=20\)

lam on giup minh voi

2:

a: =4+3/8+5+2/3

=9+3/8+2/3

=216/24+9/24+16/24

=216/24+25/24

=241/24

b; =2+3/8+1+1/4+3+6/7

=6+3/8+1/4+6/7

=6+5/8+6/7

=419/56

c: \(=2+\dfrac{3}{8}-1-\dfrac{1}{4}+5+\dfrac{1}{3}\)

=6+3/8-1/4+1/3

=6+1/8+1/3

=6+11/24

=155/24

d: \(=3+\dfrac{5}{6}+6\cdot\dfrac{13}{6}\)

=3+13+5/6

=16+5/6

=101/6

e: =3+1/2+4+5/7-5-5/14

=3+4-5+1/2+5/7-5/14

=2+7/14+10/14-5/14

=2+12/14

=2+6/7=20/7

f: =9/2+1/2:11/2

=9/2+1/11

=99/22+2/22=101/22

2:

a: =4+3/8+5+2/3

=9+3/8+2/3

=216/24+9/24+16/24

=216/24+25/24

=241/24

b; =2+3/8+1+1/4+3+6/7

=6+3/8+1/4+6/7

=6+5/8+6/7

=419/56

c: \(=2+\dfrac{3}{8}-1-\dfrac{1}{4}+5+\dfrac{1}{3}\)

=6+3/8-1/4+1/3

=6+1/8+1/3

=6+11/24

=155/24

d: \(=3+\dfrac{5}{6}+6\cdot\dfrac{13}{6}\)

=3+13+5/6

=16+5/6

=101/6

e: =3+1/2+4+5/7-5-5/14

=3+4-5+1/2+5/7-5/14

=2+7/14+10/14-5/14

=2+12/14

=2+6/7=20/7

f: =9/2+1/2:11/2

=9/2+1/11

=99/22+2/22=101/22