Question

tìm x \(\in\)N      \(x\)- \(\frac{20}{11.13}\)-\(\frac{20}{13.15}\)- \(\frac{20}{15.17}\)-.........- \(\frac{20}{53.55}\)=\(\frac{3}{11}\)

Answer 1

\(x-\frac{20}{11.13}-\frac{20}{13.15}-\frac{20}{15.17}-.....-\frac{20}{53.55}=\frac{3}{11}\)

\(x-\left(\frac{20}{11.13}+\frac{20}{13.15}+\frac{20}{15.17}+....+\frac{20}{53.55}\right)=\frac{3}{11}\)

\(x-10\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+\frac{1}{15}-\frac{1}{17}+.....+\frac{1}{53}-\frac{1}{55}\right)=\frac{3}{11}\)

\(x-10\left(\frac{1}{11}-\frac{1}{55}\right)=\frac{3}{11}\)

\(x-\frac{40}{55}=\frac{3}{11}\)

\(x=\frac{3}{11}+\frac{40}{55}\)

\(x=1\)