mik làm được mỗi ý b thui : 

b ) \(\frac{169}{10}=16,9\)

mik nha

phần đầu bằng -6675/128

phần sau bằng 13 

bạn dùng máy tính là được mà

\(\frac{7}{-25}\) \(+\) \(\frac{-18}{25}\) \(+\) \(\frac{4}{23}\) \(+\) \(\frac{5}{7}\) \(+\) \(\frac{19}{23}\) \(+\) \(\frac{2}{14}\)

\(=\)\(\frac{6}{7}\)

= 6/7 bạn nhé ^^ 

Chúc bạn học tốt . Tích cho mink nhé <3

\(=\frac{22}{25}\cdot\frac{5}{11}-\frac{22}{25}\cdot\frac{8}{9}-\frac{8}{9}\cdot\frac{27}{4}+\frac{8}{9}\cdot\frac{22}{25}\)

\(=\frac{2}{5}-6=-\frac{28}{5}\)

Bài 1:

a) Ta có: \(\frac{-5}{7}+\frac{2}{7}+\frac{4}{-9}+\frac{4}{9}\)

\(=-\frac{3}{7}+\frac{-4}{9}+\frac{4}{9}\)

\(=-\frac{3}{7}\)

b) Ta có: \(\left(\frac{1}{2}:\frac{3}{4}\right)^2\)

\(=\left(\frac{1}{2}\cdot\frac{4}{3}\right)^2\)

\(=\left(\frac{2}{3}\right)^2=\frac{4}{9}\)

c) Ta có: \(\frac{1}{2}+\frac{3}{4}-\left(\frac{4}{5}+\frac{3}{4}\right)\)

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

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

\(=\frac{5}{10}-\frac{8}{10}=\frac{-3}{10}\)

d) Ta có: \(5^6:5^4+2^3\cdot2^2-225:15^2\)

\(=5^2+2^5-\frac{15^2}{15^2}\)

\(=25+32-1\)

\(=56\)

e) Ta có: \(\frac{7}{23}+\frac{4}{17}-\frac{7}{23}+\frac{13}{17}\)

\(=\frac{4}{17}+\frac{13}{17}\)

\(=\frac{17}{17}=1\)

g) Ta có: \(19\frac{1}{4}\cdot\frac{7}{12}-15\frac{1}{4}\cdot\frac{7}{12}\)

\(=\frac{7}{12}\left(19+\frac{1}{4}-15-\frac{1}{4}\right)\)

\(=\frac{7}{12}\cdot4=\frac{7}{3}\)

\(\frac{2}{3}x-\frac{1}{2}=\frac{1}{10}\)

\(\frac{2}{3}x\)            = \(\frac{1}{10}+\frac{1}{2}\)

\(\frac{2}{3}x\)            =          \(\frac{3}{5}\)

     \(x\)             =     \(\frac{3}{5}:\frac{2}{3}\)

     \(x\)             =         \(\frac{9}{10}\)

Câu b:

(2 4/5x - 50) : 2/3 = 51

2 4/5x - 50 = 51 x 2/3

14/5x - 50 = 34

14/5x = 34 + 50

14/5x = 84

x = 84 : 14/5

x = 30

Vậy x = 30

a

\(5\frac{4}{7}:x+=13\)

\(\frac{39}{7}:x=13\)

\(x=\frac{39}{7}:13\)

\(x=\frac{3}{7}\)

\(\frac{4}{7}x=\frac{9}{8}-0,125\)

\(\frac{4}{7}x=1\)

\(x=1:\frac{4}{7}\)

\(x=\frac{7}{4}=1\frac{3}{4}\)

a) \(\left(x+\frac{1}{4}\right)^2+\frac{11}{25}=\frac{18}{25}\)

\(\Rightarrow\left(x+\frac{1}{4}\right)^2=\frac{7}{25}\)

\(\Rightarrow\) Không có x