\(\dfrac{1}{3}+\dfrac{1}{6}+....+\dfrac{2}{x\left(x+1\right)}=\dfrac{2017}{2019}\\ \Rightarrow\dfrac{2}{6}+\dfrac{2}{12}+...+\dfrac{2}{x\left(x+1\right)}=\dfrac{2017}{2019}\\ \Rightarrow2.\left(\dfrac{1}{2}-\dfrac{1}{x+1}\right)=\dfrac{2017}{2019}\\ \Rightarrow\dfrac{1}{2}-\dfrac{1}{x+1}=\dfrac{2017}{4038}\\ \Rightarrow\dfrac{1}{x+1}=\dfrac{1}{2019}\\ \Rightarrow x=2018\)
a, \(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{10}+...+\dfrac{2}{x\left(x+1\right)}=\dfrac{2015}{2017}\)
\(\left(2x-3\right)\left(6-2x\right)=0\)
\(\dfrac{1}{3}x+\dfrac{2}{5}\left(x-1\right)=0\)
\(\left(3x-1\right)\left(-\dfrac{1}{2}x+5\right)=0\)
\(\dfrac{x}{5}=\dfrac{2}{3}\)
\(\dfrac{x}{3}-\dfrac{1}{2}=\dfrac{1}{5}\)
\(\dfrac{x}{5}-\dfrac{1}{2}=\dfrac{6}{10}\)
\(\dfrac{x+3}{15}=\dfrac{1}{3}\)
\(\dfrac{x-12}{4}=\dfrac{1}{2}\)
tìm x biết
a) \(\dfrac{2x-3}{3}+-\dfrac{3}{2}=\dfrac{5-2x}{6}-\dfrac{1}{2}\)
b) \(\left(3x-\dfrac{1}{2}\right).\left(3-\dfrac{1}{2}x\right).\left(1+\dfrac{3}{4}:x\right)=0\)
c) \(\left(3-\dfrac{9}{10}-|x+2|\right):\left(\dfrac{19}{20}-1-\dfrac{2}{3}\right)+\dfrac{4}{5}=1\)
Tìm x:
a) \(\dfrac{1}{5.8}+\dfrac{1}{8.11}+\dfrac{1}{11.14}+...+\dfrac{1}{x.\left(x+3\right)}=\dfrac{101}{1540}\)
b) \(1+\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{10}+...+\dfrac{1}{x.\left(x+1\right):2}=1\dfrac{1991}{1993}\)
tìm x:
a)\(\left(x+\dfrac{1}{2}\right).\left(\dfrac{2}{3}-2x\right)=0\)
b) \(\left(x.6\dfrac{2}{7}+\dfrac{3}{7}\right).2\dfrac{1}{5}-\dfrac{3}{7}=-2\)
c) \(x.3\dfrac{1}{4}+\left(\dfrac{-7}{6}\right).x-1\dfrac{2}{3}=\dfrac{5}{12}\)
d) \(5\dfrac{8}{17}:x+\left(-\dfrac{4}{17}\right):x+3\dfrac{1}{7}:17\dfrac{1}{3}=\dfrac{4}{11}\)
Tìm x biết:
a) \(\dfrac{x+5}{3}\)=\(\dfrac{x-6}{7}\)
b) x - \(\dfrac{20}{11.13}\)-\(\dfrac{20}{13.15}\)-\(\dfrac{20}{15.17}\)-...-\(\dfrac{20}{53.55}\)=\(\dfrac{3}{11}\)
\(\dfrac{1}{3}\)+\(\dfrac{1}{6}\)+\(\dfrac{1}{10}\)+...+\(\dfrac{2}{n\left(n+1\right)}\)=\(\dfrac{2015}{2016}\)
a, \(\dfrac{5}{2}-3\left(\dfrac{1}{3}-x\right)=\dfrac{1}{4}-7x\)
b,\(60\%.x+\dfrac{2}{3}.x=\dfrac{1}{3}.6\dfrac{1}{3}\)
c, \(\left(\dfrac{9}{2}.x-2x\right).\left(-1\dfrac{4}{7}\right)=\dfrac{11}{4}\)
d,\(\left(x+\dfrac{5}{6}\right).2\dfrac{2}{5}-1\dfrac{1}{4}=35\%\)
Tìm x:
a)\(2016x+\left(\dfrac{7}{12}+\dfrac{4}{21}+\dfrac{2}{24}+\dfrac{11}{30}+\dfrac{3}{40}+\dfrac{15}{56}\right)-\left(\dfrac{2}{3}+\dfrac{2}{4}+\dfrac{2}{5}\right)=0\)
b\(\dfrac{2x-1}{x+2015}-\dfrac{4025}{x+2017}=\dfrac{x-2014}{2x-4036}-\dfrac{x-2013}{2x-4030}\) (x thuộc N)
c)\(\left(1+\dfrac{1}{1.3}\right)\left(1+\dfrac{1}{2.4}\right)\left(1+\dfrac{1}{3.5}\right)...\left(1+\dfrac{1}{x\left(x+2\right)}\right)=\dfrac{4016}{2007}\)
AI GIÚP MK VỚI MK TICK CHO 
Tìm số x , biết
a) \(\dfrac{2}{3}x-\dfrac{3}{2}x=\dfrac{5}{12}\)
b) \(\dfrac{2}{5}+\dfrac{3}{5}.\left(3x-3,7\right)=-\dfrac{53}{10}\)
c) \(\dfrac{7}{9}:\left(2+\dfrac{3}{4}x\right)+\dfrac{5}{9}=\dfrac{23}{27}\)
d) \(\dfrac{-2}{3}.x+\dfrac{1}{5}=\dfrac{3}{10}\)
e) \(\left|x\right|-\dfrac{3}{4}=\dfrac{5}{3}\)
f) \(\left|2x-\dfrac{1}{3}\right|+\dfrac{5}{6}=1\)