Bài làm:

\(\left(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}\right).y=\frac{2}{3}\)

\(\Leftrightarrow\left(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}\right).y=\frac{4}{3}\)

\(\Leftrightarrow\left(\frac{3-1}{1.3}+\frac{5-3}{3.5}+\frac{7-5}{5.7}+\frac{9-7}{7.9}+\frac{11-9}{9.11}\right).y=\frac{4}{3}\)

\(\Leftrightarrow\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\right).y=\frac{4}{3}\)

\(\Leftrightarrow\left(1-\frac{1}{11}\right).y=\frac{4}{3}\)

\(\Leftrightarrow\frac{10}{11}.y=\frac{4}{3}\)

\(\Leftrightarrow y=\frac{4}{3}:\frac{10}{11}=\frac{4}{3}.\frac{11}{10}=\frac{22}{15}\)

Chú ý dấu \(\left(.\right)\)là dấu \(\left(\times\right)\)

Vậy \(y=\frac{22}{15}\)

\(\left(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}\right).y=\frac{2}{3}\)

\(\Leftrightarrow\frac{1}{2}.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\right).y=\frac{2}{3}\)

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

\(\Leftrightarrow\frac{1}{2}.\frac{10}{11}.y=\frac{2}{3}\)

\(\Leftrightarrow\frac{5}{11}.y=\frac{2}{3}\)

\(\Rightarrow y=\frac{2}{3}:\frac{5}{11}=\frac{22}{15}\)

LƯU Ý:các dấu chấm(.) là dấu nhân ^^.

(\(\frac{1}{1\cdot3}+\frac{1}{3\cdot5}+\frac{1}{5\cdot7}+\frac{1}{7\cdot9}+\frac{1}{9\cdot11}\)) *y = \(\frac{2}{3}\)

\(x\times\frac{3}{5}-\frac{1}{2}=\frac{4}{5}\)

\(\Rightarrow x\times\frac{6}{10}-\frac{5}{10}=\frac{4}{5}\)

\(\Rightarrow x\times\frac{1}{10}=\frac{4}{5}\)

\(\Rightarrow x=\frac{4}{5}:\frac{1}{10}\)

\(\Rightarrow x=\frac{4}{5}\cdot\frac{10}{1}\)

\(\Rightarrow x=\frac{40}{5}=8\)

Vậy x = 8

\(x\times\frac{3}{5}-\frac{1}{2}=\frac{4}{5}\)

\(x\times\frac{3}{5}=\frac{4}{5}+\frac{1}{2}\)

\(x\times\frac{3}{5}=\frac{13}{10}\)

\(x=\frac{13}{10}:\frac{3}{5}\)

\(x=\frac{13}{6}\)

Lộn :D

\(x\cdot\frac{3}{5}-\frac{1}{2}=\frac{4}{5}\)

\(\Rightarrow x\cdot\frac{3}{5}=\frac{4}{5}+\frac{1}{2}\)

\(\Rightarrow x\cdot\frac{3}{5}=\frac{8}{10}+\frac{5}{10}\)

\(\Rightarrow x\cdot\frac{3}{5}=\frac{13}{10}\)

\(\Rightarrow x=\frac{13}{10}:\frac{3}{5}=\frac{65}{30}=\frac{13}{6}\)

Ta có:       x:7/8+3/4=7/4

                -> x:7/8=7/4-3/4

                ->x:7/8=1

                ->x=1*7/8

                ->x=7/8

                  Vậy x=7/8

\(x\div\frac{7}{8}+\frac{3}{4}=\frac{7}{4}\)

\(\Rightarrow x\div\frac{7}{8}=\frac{7}{4}-\frac{3}{4}\)

\(\Rightarrow x\div\frac{7}{8}=1\)

\(\Rightarrow x=1\times\frac{7}{8}\)

\(\Rightarrow x=\frac{7}{8}\)

\(\frac{x:7}{8}+\frac{3}{4}=\frac{7}{4}\)

\(\frac{x:7}{8}+\frac{6}{8}=\frac{14}{8}\)

\(\Rightarrow x:7+6=14\)

\(x:7=14-6\)

\(x:7=8\)

\(x=8\cdot7\Rightarrow x=56\)

Bạn thấy những ô phía trên khung đặt câu hỏi hay câu trả lời ko? Bạn vào cái ô công thức Toán ở cạnh ô Tex đó. Ở đó bạn chọn biểu tượng phân số là xong.

\(\dfrac{1}{2}-\dfrac{1}{2}\left(3-2x\right)=0\)

\(\Rightarrow\dfrac{1}{2}\left[1-\left(3-2x\right)\right]=0\)

\(\Rightarrow\dfrac{1}{2}\left[1-3+2x\right]=0\)

\(\Rightarrow\dfrac{1}{2}\left[2x-2\right]=0\)

\(\Rightarrow2x-2=0\Rightarrow2x=2\Rightarrow x=1\)

x = 1 nha Nhật

`x-10/3=7/18+3/5`

`=> x-10/3=89/90`

`=> x=89/90+10/3`

`=> x=389/90`

thanhk you:)

bài2 \(x\times\dfrac{15}{16}-x\times\dfrac{4}{16}=2\) 

     \(x\times\dfrac{11}{16}=2\) 

     \(x=2:\dfrac{11}{16}\) 

    \(x=\dfrac{32}{11}\)

Bài 1 : 

 \(\dfrac{x}{16}\times\left(2017-1\right)=2\)

          \(\dfrac{x}{16}\times2016=2\)

                      \(\dfrac{x}{16}=\dfrac{2}{2016}\)

                         \(x=\dfrac{2}{2016}\times16\)

                         \(x=\dfrac{1}{63}\)

1- (5\(\dfrac{4}{9}\) +x+7\(\dfrac{7}{18}\)) : 15\(\dfrac{3}{4}\) = 0 

1- (\(\dfrac{49}{9}+x+\dfrac{133}{18}\)) : \(\dfrac{63}{4}=0\) 

 (\(\dfrac{49}{9}+\dfrac{133}{18}\)+\(x\) ) : \(\dfrac{63}{4}\) = 1 - 0 

       (\(\dfrac{77}{6}\) + \(x\) ) : \(\dfrac{63}{4}\) = 1

         \(\dfrac{77}{6}+x\)         = 1 x \(\dfrac{63}{4}\) 

          \(\dfrac{77}{6}\) + \(x\)          = \(\dfrac{63}{4}\)

                  \(x\)            = \(\dfrac{63}{4}\) - \(\dfrac{77}{6}\)

                  \(x=\) \(\dfrac{35}{12}\)

\(x-\frac{6}{5}\div\frac{2}{3}=\frac{5}{6}\)

\(\Leftrightarrow x-\frac{18}{10}=\frac{5}{6}\)

\(\Leftrightarrow x=\frac{5}{6}+\frac{18}{10}\)

\(\Leftrightarrow x=\frac{25}{30}+\frac{54}{30}\)

\(\Leftrightarrow x=\frac{79}{30}\)

\(x-\frac{6}{5}\div\frac{2}{3}=\frac{5}{6}\)

\(x-\frac{18}{10}=\frac{5}{6}\)

\(x=\frac{5}{6}+\frac{18}{10}\)

\(\Rightarrow x=\frac{79}{30}\)