\(\frac{3}{2}x-\frac{11}{5}=\frac{7}{8}.\frac{64}{49}\)

\(\frac{3}{2}x-\frac{11}{5}=\frac{8}{7}\)

\(\frac{3}{2}x=\frac{8}{7}+\frac{11}{5}=\frac{117}{35}\)

\(x=\frac{117}{35}:\frac{3}{2}=\frac{78}{35}\)

\(\frac{3}{2}x-\frac{11}{5}=\frac{7}{8}.\frac{64}{49}\) 

\(\frac{3}{2}x-\frac{11}{5}=\frac{8}{7}\)

\(\frac{3}{2}x=\frac{8}{7}+\frac{11}{5}\)

\(\frac{3}{2}x=\frac{117}{35}\)

\(x=\frac{117}{35}:\frac{3}{2}\)

\(x=\frac{78}{35}\)

1.Vì  \(\frac{x}{-2}=\frac{-8}{x}\Rightarrow-2.\left(-8\right)=x.x\)

                                        \(16=x.x\)hay \(4^2=x^2\Rightarrow x=4\)

2. Rút gọn : \(\frac{20}{28}=\frac{5}{7}=\frac{-5}{-7}\)

\(\Rightarrow x=-7\)

3. \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)

\(\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)

Mà \(\frac{8}{7}+\frac{11}{5}=\frac{502}{35}\)

\(\Rightarrow x=\frac{234}{35}\)

1) \(\frac{x}{-2}=\frac{-8}{x}\)

\(\Rightarrow x\times x=\left(-2\right)\times\left(-8\right)\)

\(\Rightarrow x^2=16\)

\(\Rightarrow\orbr{\begin{cases}x^2=4^2\\x^2=\left(-4\right)^2\end{cases}\Rightarrow}\orbr{\begin{cases}x=4\\x=-4\end{cases}}\)

Vậy x = 4 hoặc x = -4

2) \(\frac{-5}{x}=\frac{20}{28}\)

\(\Rightarrow\frac{-5}{x}=\frac{5}{7}\)

\(\Rightarrow5\times x=\left(-5\right)\times7\)

\(\Rightarrow5\times x=-35\)

\(\Rightarrow x=\left(-35\right):5\)

\(\Rightarrow x=-7\)

Vậy x = -7

3) \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)

\(\Rightarrow\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)

\(\Rightarrow\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)

\(\Rightarrow\frac{x}{2}=\frac{117}{35}\)

\(\Rightarrow35x=117\times2\)

\(\Rightarrow35x=234\)

\(\Rightarrow x=234:35\)

\(\Rightarrow x=\frac{234}{35}\)

Vậy  \(x=\frac{234}{35}\)

4) \(\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{36}{48}\)

\(\Rightarrow\frac{x}{5}+\frac{9}{2}=\frac{9}{14}\)

\(\Rightarrow\frac{x}{5}=\frac{9}{14}-\frac{9}{2}\)

\(\Rightarrow\frac{x}{5}=\frac{-27}{7}\)

\(\Rightarrow7x=\left(-27\right)\times5\)

\(\Rightarrow7x=-135\)

\(\Rightarrow x=\left(-135\right):7\)

\(\Rightarrow x=\frac{-135}{7}\)

Vậy  \(x=\frac{-135}{7}\)

5) \(\frac{3}{x-5}=\frac{-4}{x+2}\)

\(\Rightarrow\frac{3}{x-5}+\frac{4}{x+2}=0\)

\(\Rightarrow3\left(x+2\right)+4\left(x-5\right)=0\)

\(\Rightarrow3x+6+4x-20=0\)

\(\Rightarrow\left(3x+4x\right)+\left(6-20\right)=0\)

\(\Rightarrow7x-14=0\)

\(\Rightarrow7x=14\)

\(\Rightarrow x=14:7\)

\(\Rightarrow x=2\)

Vậy x = 2

_Chúc bạn học tốt_

\(1.\frac{x}{-2}=\frac{-8}{x}\)

\(\Rightarrow x\times x=\left(-8\right)\times\left(-2\right)\)

           \(x^2=16\)

        \(\Rightarrow x=4\)

       Vậy\(x=4\)

\(2.\frac{-5}{x}=\frac{20}{28}\)

\(\frac{-5}{x}=\frac{5}{7}\)

\(\frac{-5}{x}=\frac{-5}{-7}\)

  \(\Rightarrow x=-7\)

 Vậy\(x=-7\)

\(3.\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)

    \(\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)

                 \(\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)

                 \(\frac{x}{2}=\frac{40+77}{35}\)

                 \(\frac{x}{2}=\frac{117}{35}\)

         \(x\times35=117\times2\)

               \(35x=234\)

                    \(x=\frac{234}{35}\)

              Vậy\(x=\frac{234}{35}\)

\(4.\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{36}{48}\)

   \(\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{3}{4}\)

   \(\frac{x}{5}+\frac{9}{2}=\frac{9}{14}\)

              \(\frac{x}{5}=\frac{9}{14}-\frac{9}{2}\)

             \(\frac{x}{5}=\frac{9}{14}-\frac{63}{14}\)

             \(\frac{x}{5}=\frac{-54}{14}\)

             \(\frac{x}{5}=\frac{-27}{7}\)

             \(7x=\left(-27\right)\times5\)

             \(7x=-135\)

               \(x=\frac{-135}{7}\)

         Vậy\(x=\frac{-135}{7}\)

\(5.\frac{3}{x-5}=\frac{-4}{x+2}\)

\(3\times\left(x+2\right)=\left(-4\right)\times\left(x-5\right)\)

           \(3x+6=\left(-4\right)x+20\)

        \(3x+4x=20-6\)

                  \(7x=14\)

                    \(x=14\div7\)

                    \(x=2\)

              Vậy\(x=2\)

\(c)\) \(C=\frac{\frac{2}{7}+\frac{2}{5}+\frac{2}{17}-\frac{2}{293}}{\frac{3}{7}+\frac{3}{5}+\frac{3}{17}-\frac{3}{293}}\)

\(C=\frac{2\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}-\frac{1}{293}\right)}{3\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}-\frac{1}{193}\right)}\)

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

Bạn Cô nàng Thiên Bình làm đúng hết òi =.= 

a=7.[1/8+1/27-1/49]

   ------------------------

11.[1/8+1/27-1/49]

=7/11

cau b,c tuong tu nha h mk   

a)\(A=\frac{\frac{7}{8}+\frac{7}{27}-\frac{7}{49}}{\frac{11}{8}+\frac{11}{27}-\frac{11}{49}}\)

\(A=\frac{7.\left(\frac{1}{8}+\frac{1}{27}-\frac{1}{49}\right)}{11.\left(\frac{1}{8}+\frac{1}{27}-\frac{1}{49}\right)}\).

\(A=\frac{7}{11}\)

b)\(B=\frac{\frac{8}{9}-\frac{8}{27}-\frac{8}{81}+\frac{8}{243}}{4-\frac{4}{3}-\frac{4}{9}+\frac{4}{27}}\)

\(B=\frac{\frac{8}{9}.\left(1-\frac{1}{3}-\frac{1}{9}+\frac{1}{27}\right)}{4.\left(1-\frac{1}{3}-\frac{1}{9}+\frac{1}{27}\right)}\)

\(B=\frac{8}{9}:4=\frac{2}{9}\)

c)\(C=\frac{\frac{2}{7}+\frac{2}{5}+\frac{2}{17}-\frac{2}{293}}{\frac{3}{7}+\frac{3}{5}+\frac{3}{17}-\frac{3}{293}}\)\(C=\frac{2.\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}-\frac{1}{239}\right)}{3.\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}-\frac{1}{239}\right)}\)

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

a Đ

b S

c S

d Đ

a ) S 

b ) Đ

c ) S

d ) Đ

k cho mk nhé 

Mai Hồng Ngọc? Vũ Thị Thu Hằng? Ai đúng dzậy -_-*

1, Tính tổng:

\(C=\frac{5}{7}\cdot\frac{5}{11}+\frac{5}{7}\cdot\frac{2}{11}-\frac{5}{7}\cdot\frac{14}{11}\)

\(=\frac{5}{7}\cdot\left(\frac{5}{11}+\frac{2}{11}-\frac{14}{11}\right)=\frac{5}{7}\cdot\frac{-7}{11}=\frac{-5}{11}\)

2, Tìm x:

\(x+\frac{5}{5\cdot9}+\frac{4}{9\cdot13}+\frac{4}{13\cdot17}+...+\frac{4}{41\cdot45}=\frac{-37}{45}\)

\(\Rightarrow x+\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+\frac{1}{13}-\frac{1}{17}+...+\frac{1}{41}-\frac{1}{45}=\frac{-37}{45}\)

\(\Rightarrow x+\frac{1}{5}-\frac{1}{45}=\frac{-37}{45}\Rightarrow x+\frac{9}{45}-\frac{1}{45}=\frac{-37}{45}\)

\(\Rightarrow x+\frac{8}{45}=\frac{-37}{45}\Rightarrow x=\frac{-37}{45}-\frac{8}{45}=\frac{-45}{45}=-1\)

- Các bài tìm x còn lại bạn cứ theo trình tự thực hiện phép tính mà làm nhé!

\(C=\frac{5}{7}\cdot\frac{5}{11}+\frac{5}{7}\cdot\frac{2}{11}-\frac{5}{7}\cdot\frac{14}{11}\)

\(=\frac{5}{7}\cdot\left(\frac{5}{11}+\frac{2}{11}-\frac{14}{11}\right)\)

\(=\frac{5}{7}\cdot-\frac{7}{11}\)

\(=-\frac{5}{11}\)

\(C=\frac{5}{7}.\frac{5}{11}+\frac{5}{7}.\frac{2}{11}-\frac{5}{7}.\frac{14}{11}\)

\(\Leftrightarrow C=\frac{5}{7}\left(\frac{5}{11}+\frac{2}{11}-\frac{14}{11}\right)\)

\(\Leftrightarrow C=\frac{5}{7}\times\frac{-7}{11}\)

\(\Leftrightarrow C=\frac{-35}{77}=\frac{-5}{11}\)

a) \(\frac{1}{9}\)

b) -1100

\(\frac{\left(\frac{5}{8}+\frac{5}{27}-\frac{5}{49}\right)\cdot8\cdot27\cdot49}{\left(\frac{11}{8}+\frac{11}{27}-\frac{11}{49}\right)\cdot8\cdot27\cdot49}+\frac{6}{11}\)

\(=\frac{8+27-49}{8+27-49}+\frac{6}{11}\)

\(=1+\frac{6}{11}\)

\(=\frac{11}{11}+\frac{6}{11}=\frac{17}{11}\)

\(\frac{\frac{5}{8}+\frac{5}{27}-\frac{5}{49}}{\frac{11}{8}+\frac{11}{27}-\frac{11}{49}}+\frac{6}{11}\)

\(=\frac{5\left(\frac{1}{8}+\frac{1}{27}-\frac{1}{49}\right)}{11\left(\frac{1}{8}+\frac{1}{27}-\frac{1}{49}\right)}+\frac{6}{11}\)

\(=\frac{5}{11}+\frac{6}{11}=\frac{11}{11}=1\)

Chép lại đề bài!

\(=\frac{5.(\frac{1}{8}+\frac{1}{27}-\frac{1}{49})}{11.(\frac{1}{8}+\frac{1}{27}-\frac{1}{49})}+\frac{6}{11}\)

\(=\frac{5}{11}+\frac{6}{11}\)

\(=\frac{11}{11}=1\)

Câu 1;

\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}\cdot\frac{\frac{3}{4}-\frac{3}{16}-\frac{3}{64}-\frac{3}{256}}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}\)

\(=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{2\left(\frac{1}{3}-\frac{1}{7}-\frac{1}{13}\right)}\cdot\frac{3\left(\frac{1}{4}-\frac{1}{16}-\frac{1}{64}-\frac{1}{256}\right)}{4\left(\frac{1}{4}-\frac{1}{16}-\frac{1}{64}-\frac{1}{256}\right)}+\frac{5}{8}\)

\(=\frac{1}{2}\cdot\frac{3}{4}+\frac{5}{8}=\frac{3}{8}+\frac{5}{8}=1\)

Câu 2:

\(\frac{0,75-0,6+\frac{3}{7}+\frac{3}{13}}{2,75-2,2+\frac{11}{7}+\frac{11}{3}}=\frac{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{13}}{\frac{11}{4}-\frac{11}{5}+\frac{11}{7}+\frac{11}{3}}=\frac{3\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}{11\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}=\frac{3}{11}\)

Câu 1;

13 −17 −113 23 −27 −213  ·34 −316 −364 −3256 1−14 −116 −164  +58 

=13 −17 −113 2(13 −17 −113 ) ·3(14 −116 −164 −1256 )4(14 −116 −164 −1256 ) +58 

=12 ·34 +58 =38 +58 =1

Câu 2:

rút gọn tu , bạn ơi