#)Giải :
( k chép lại đề )
\(x=\frac{1}{5}\left(\frac{5}{5.10}-\frac{5}{10.15}-...-\frac{5}{95.100}\right)\)
\(x=\frac{1}{5}\left(\frac{1}{5}-\frac{1}{10}+\frac{1}{10}-\frac{1}{15}+...+\frac{1}{95}-\frac{1}{100}\right)\)
\(x=\frac{1}{5}\left(\frac{1}{5}-\frac{1}{100}\right)\)
\(x=\frac{1}{5} . \frac{19}{100}\)
\(x=\frac{19}{500}\)