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