Tìm x biết \(\left(\frac{1}{1\cdot101}+\frac{1}{2\cdot101}+...+\frac{1}{10\cdot101}\right)\cdot x=\frac{1}{1\cdot11}+\frac{1}{2\cdot12}+...+\frac{1}{100\cdot110}\)
tìm x biết:
\(\left(\frac{1}{1\cdot101}+\frac{1}{2\cdot101}+...+\frac{1}{10\cdot101}\right)\cdot x=\frac{1}{1\cdot11}+\frac{1}{2\cdot12}+...+\frac{1}{100\cdot110}\)
Tìm x biết: \(\left(\frac{1}{1.101}+\frac{1}{2.102}+...+\frac{1}{10.110}\right).x=\frac{1}{1.11}+\frac{1}{2.12}+...+\frac{1}{100.110}\)
\(\frac{\left(1+2+...+100\right)\cdot\left(\frac{1}{3}-\frac{1}{5}-\frac{1}{7}-\frac{1}{9}\right)\cdot\left(6,3\cdot12-21\cdot3,6\right)}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)
1/ Tính
a) \(P=1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+\frac{1}{4}\left(1+2+3+4\right)+...+\frac{1}{16}\left(1+2+3+...+16\right)\)
b) Cho \(a+b+c=2010\)và \(\frac{1}{a+b}+\frac{1}{b+c}+\frac{1}{c+a}=\frac{1}{3}\)
Tính \(S=\frac{a}{b+c}+\frac{b}{c+a}+\frac{c}{a+b}\)
2/ Tìm x biết
\(\frac{1}{4}\cdot\frac{2}{6}\cdot\frac{3}{8}\cdot\frac{4}{10}...\frac{30}{62}\cdot\frac{31}{64}=2^x\)
3/ Tìm \(a_1;a_2;a_3;...;a_{100}\)biết \(\frac{a_1-1}{100}=\frac{a_2-2}{99}=\frac{a_3-3}{98}=...=\frac{a_{100}-100}{1}\)và \(a_1+a_2+a_3+...+a_{100}=10100\)
Tìm x biết :
a, ( 4x - 9 ) . ( 2,5 + \(\frac{-7}{3}\). x ) = 0
b, \(\frac{1}{x\cdot\left(x+1\right)}\cdot\frac{1}{\left(x+1\right)\cdot\left(x+2\right)}\cdot\frac{1}{\left(x+2\right)\cdot\left(x+3\right)}-\frac{1}{x}=\frac{1}{2015}\)
TÌM x
\(\left(\left(\frac{3}{4}\cdot x+5\right)-\left(\frac{2}{3}\cdot x-4\right)-\left(\frac{1}{6}\cdot x+1\right)\right)=\left(\frac{1}{3}\cdot x+4\right)-\left(\frac{1}{3}-3\right)\)
TÌM X
\(\left(\frac{1}{7}x-\frac{2}{7}\right)\cdot\left(-\frac{1}{5}x+\frac{3}{5}\right)\cdot\left(\frac{1}{3}x+\frac{4}{3}\right)=0\)
\(\left(\frac{1}{7}\cdot x-\frac{2}{7}\right)\cdot\left(-\frac{1}{5}\cdot x+\frac{3}{5}\right)\cdot\left(\frac{1}{3}\cdot x+\frac{4}{3}\right)=0\)