Question

[Best Friend]

     tìm x trong biểu thức :

( \(\frac{1}{1\cdot2}\)+ \(\frac{1}{2\cdot3}\)+ \(\frac{1}{3\cdot4}\)+........+ \(\frac{1}{8\cdot9}\)+ \(\frac{1}{9\cdot10}\)) *100 - \([\)\(\frac{5}{2}\): ( X + \(\frac{206}{100}\) ) \(]\):\(\frac{1}{2}\)= 89 ..

     Giúp mk nha ai nhanh mk tk

Answer 1

[Dương Lam Hàng]

\(\left(\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{8.9}+\frac{1}{9.10}\right)\times100-\left[\frac{5}{2}:\left(x+\frac{206}{100}\right)\right]:\frac{1}{2}=89\)

\(\Rightarrow\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{9}-\frac{1}{10}\right)\times100-\left[\frac{5}{2}:\left(x+\frac{206}{100}\right)\right]=\frac{89}{2}\)

\(\Rightarrow\left(1-\frac{1}{10}\right)\times100-\left[\frac{5}{2}:\left(x+\frac{206}{100}\right)\right]=\frac{89}{2}\)

Answer 2

[Đỗ Minh Quân]

<=>9/10