\(\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right)\left(1-\frac{1}{5}\right)=\frac{x}{100}\)
\(\Rightarrow\frac{1}{2}.\frac{2}{3}.\frac{3}{4}.\frac{4}{5}=\frac{x}{100}\)
\(\Rightarrow\frac{1}{5}=\frac{x}{100}\)
\(\Rightarrow x=\frac{100.1}{5}=20\)
Tìm x biết
\(\frac{2}{3}+x=\frac{-4}{5}\)\(\frac{2}{5}-x=\frac{-1}{3}\)\(1-\frac{x}{3}=1\frac{1}{2}\)\(1-\left(\frac{2x}{3}+2\right)=-1\frac{1}{3}\)tìm x biết :
a) \(\left(x+\frac{1}{2}\right).\left(\frac{2}{3}-2x\right)=0\)
b) \(\left(x.6\frac{2}{7}+\frac{3}{7}\right).2\frac{1}{5}-\frac{3}{7}=-2\)
c) \(x.3\frac{1}{4}+\left(-\frac{7}{6}\right).x-1\frac{2}{3}=\frac{5}{12}\)
d) \(5\frac{8}{17}:x+\left(-\frac{4}{17}\right):x+3\frac{1}{7}:17\frac{1}{3}=\frac{4}{11}\)
e) \(\frac{17}{2}-\left|2x-\frac{3}{4}\right|=-\frac{7}{4}\)
Bài 14 : Tìm x biết :
e) \(\frac{-2}{3}-\frac{1}{3}\left(2x-5\right)=\frac{3}{2}\) g) \(\frac{2}{5}x+\frac{1}{2}=\frac{-3}{4}\) h) \(\frac{1}{3}x-8=\frac{1}{2}\) i) \(x-\frac{1}{4}=\frac{5}{8}.\frac{2}{3}\)
Tìm x biết
a) x + \(2\frac{3}{4}=5\frac{2}{3}\)
b)X x \(3\frac{1}{2}=4\frac{3}{4}\)
c) x - \(4\frac{1}{5}=3\frac{2}{7}\)
d) x - \(\frac{3}{4}=6\text{x}\frac{3}{8}\)
e) \(\frac{7}{8}:x=3\frac{1}{2}\)
Bài 14 : Tìm x biết :
a) x: \(4\frac{1}{3}=-2,5\) b) x: \(\frac{-3}{5}=\frac{-10}{21}\) c) \(\frac{2}{3}x-\frac{1}{2}=\frac{1}{10}\) d) \(\frac{1}{2}x+\frac{1}{2}=\frac{5}{2}\)
tìm x biết :
a) \(\frac{6}{7}.x=\frac{18}{23}\)
b) \(2\frac{1}{2}.x=\frac{5}{6}\)
c) \(x:2\frac{3}{4}=9\frac{5}{8}\)
d)\(7\frac{1}{7}.\frac{1}{7}.x=22\frac{1}{8}\)
Tính nhanh :
\(\frac{1}{1}x\frac{1}{2}+\frac{1}{2}x\frac{1}{3}+\frac{1}{3}x\frac{1}{4}+\frac{1}{4}x\frac{1}{5}+\frac{1}{5}x\frac{1}{6}\)
Giúp mình với nha <3 Chiều mai mình đi học rồi 
Tìm số tự nhiên x biết:
\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+.....+\frac{2}{x.\left(x+1\right)}=\frac{1999}{2001}\)
\(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+....+\frac{2}{x.\left(x+1\right)}\)
