Trả lời :

Dấu " - " của phần b trong phần của pn làm đou roy hả pn (: ?

Đúng sai thặc mak 

Hok tốt

đề là tìm x,y 

phải có 1 kết luận

a) \(\frac{27}{8}\times\frac{5}{7}\times\frac{8}{27}+\frac{2}{7}\)

\(=\frac{27\times5\times8}{8\times7\times27}+\frac{2}{7}\)

\(=\frac{5}{7}+\frac{2}{7}\)

\(=1\)

b) \(1,6\times\frac{25}{32}-\left(\frac{2}{3}+\frac{4}{5}\right):\frac{11}{5}\)

\(=\frac{8}{5}\times\frac{25}{32}-\left(\frac{2}{3}+\frac{4}{5}\right).\frac{5}{11}\)

\(=\frac{5}{4}-(\frac{10}{33}+\frac{4}{11})\)

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

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

chịu luôn rùi! !   phần b, mk ko tính nhanh đc! cho mk xin lỗi bn nhiều nha!

1. \(x=\frac{61}{42}\)

2. \(x=\frac{-36}{5}\) 

3. \(x=\frac{13}{11}\)

4. \(x=\frac{1}{12}\)

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

\(1,\)\(x-\frac{3}{5}=\frac{3}{35}-\frac{-7}{6}\)

        \(x-\frac{3}{5}=\frac{3}{35}+\frac{7}{6}\)

        \(x-\frac{3}{5}=\frac{263}{210}\)

                    \(x=\frac{263}{210}+\frac{3}{5}\)

                    \(x=\frac{389}{210}\)

        VẬY: \(x=\frac{389}{210}\)

\(a,\frac{1-2x}{8}=\frac{-4}{2\left(2x-1\right)}\)

\(\Rightarrow2\left(1-2x\right)\left(2x-1\right)=-32\)

\(\Rightarrow2\left(2x-1\right)\left(2x-1\right)=32\)

\(\Rightarrow\left(2x-1\right)^2=16\)

\(\Rightarrow\orbr{\begin{cases}2x-1=4\\2x-1=-4\end{cases}\Rightarrow\orbr{\begin{cases}2x=5\\2x=-3\end{cases}\Rightarrow}\orbr{\begin{cases}x=\frac{5}{2}\\x=-\frac{3}{2}\end{cases}}}\)

\(b,\frac{-2}{x-1}=\frac{1-x}{\frac{8}{25}}\)

\(\Leftrightarrow(x-1)(1-x)=-\frac{16}{25}\)

\(\Leftrightarrow-(x-1)^2=-\frac{16}{25}\)

\(\Leftrightarrow-(x+1)^2=\left[-\frac{4}{5}\right]^2=\left[\frac{4}{5}\right]^2\)

\(\Leftrightarrow\orbr{\begin{cases}-x+1=-\frac{4}{5}\\-x+1=\frac{4}{5}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{9}{5}\\x=\frac{1}{5}\end{cases}}\)

a) \(\frac{x-1}{x+5}=\frac{6}{7}\Rightarrow7\left(x-1\right)=6\left(x+5\right)\)

                                   7x - 7 = 6x +30

                                    7x-6x=30+7

                                    x=37

b)\(\frac{-2}{x}=\frac{-x}{\frac{8}{25}}\Rightarrow-x^2=-\frac{16}{25}\)

                                     x²=16/25

=>  x = 4/5 hoặc x=-4/5

\(a)x=37\)

\(b)x=\frac{-4}{5}\)

bài 1.a)\(A=\frac{9^3.25^3}{18^2.125^2}=\frac{3^6.5^6}{2^2.3^4.5^6}=\frac{9}{4}\)

b) \(B=\frac{18}{37}+\frac{19}{37}+\frac{8}{2017}-\frac{4026}{2017}+\frac{2017}{2018}\)

\(=1-\frac{4014}{2017}+\frac{2017}{2018}=\frac{1997}{2017}+\frac{2017}{2018}\)