Question

bài 2 : Tìm x
x/2022 - 1/10 - 1/15 - 1/21 - .... - 1/120 = 5/8

Answer 1

\(\Leftrightarrow\dfrac{x}{2022}-2\left(\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{41}+...+\dfrac{1}{240}\right)=\dfrac{5}{8}\)

\(\Leftrightarrow x:2022-2\cdot\left(\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{6}+...+\dfrac{1}{15}-\dfrac{1}{16}\right)=\dfrac{5}{8}\)

\(\Leftrightarrow x:2022-2\cdot\dfrac{3}{16}=\dfrac{5}{8}\)

=>x:2022=1

=>x=2022

Answer 2

=x:2022−2⋅(14−15+15−16+...+115−116)=58⇔x:2022−2⋅(14−15+15−16+...+115−116)=58