x/186 = (1 - 303030/313131) + (616161/626262 - 1) + (929292/939393 - 1)
x/186 = 1 - 30/31 + 61/62 - 1 + 92/93 - 1
x/186 = 61/62 - 30/31 + 92/93 - 1
x/186 = 1/62 - 1/93
x/186 = 1/186
x = 1
12) X/186=(1-303030/313131)+(616161/626262-1)+(929292/939393-1)
\(\dfrac{\left(1-\dfrac{1}{6}\right)+\left(1-\dfrac{2}{7}\right)+\left(1-\dfrac{3}{8}\right)+...+\left(1-\dfrac{88}{93}\right)}{\dfrac{-1}{12}-\dfrac{1}{14}-\dfrac{1}{16}-...-\dfrac{1}{186}}\)
\(\dfrac{\left(1-\dfrac{1}{6}\right)+\left(1-\dfrac{2}{7}\right)+\left(1-\dfrac{3}{8}\right)+...+\left(1-\dfrac{88}{93}\right)}{\dfrac{-1}{12}-\dfrac{1}{14}-\dfrac{1}{16}-...-\dfrac{1}{186}}\)
Tìm x:
a) \(\dfrac{1}{3}.x+\dfrac{2}{5}\left(x-1\right)=0\)
b)\(-5.\left(x+\dfrac{1}{5}\right)-\dfrac{1}{2}.\left(x-\dfrac{2}{3}\right)=x\)
c)\(\left(x+\dfrac{1}{2}\right).\left(\dfrac{2}{3}-2x\right)=0\)
d)\(9.\left(3x+1\right)^2=16\)
Tìm x liên quan đến lũy thừa:
1, \(\left(3x-\dfrac{1}{5}\right)^2=\left(\dfrac{-3}{25}\right)^2\)
2, \(\left(2x-\dfrac{1}{3}\right)^2=\left(\dfrac{-2}{9}\right)^2\)
3, \(\left(\dfrac{1}{3}-x\right)^2=\dfrac{9}{25}\)
4, \(\left(5-x\right)^2=25\)
tìm x
\(\dfrac{3-x}{5-x}=\dfrac{6}{11}\) \(\left(1\dfrac{1}{3}-25\%.x-\dfrac{5}{12}\right)-2x=1,6:\dfrac{3}{5}\)
\(\dfrac{1}{2}.\left(x-\dfrac{2}{3}\right)-\dfrac{1}{3}.\left(2x-3\right)=x\)
\(2.\left(\dfrac{1}{2}-x\right)-3\left(x-\dfrac{1}{3}\right)=\dfrac{7}{2}\)
Tính hợp lý
\(A = \left(1-\dfrac{1}{25}\right)\left(1-\dfrac{1}{36}\right)\left(1-\dfrac{1}{49}\right)...\left(1-\dfrac{1}{10000}\right)\) B= \(\left(1-\dfrac{1}{3}\right)\left(1-\dfrac{1}{6}\right)\left(1-\dfrac{1}{10}\right)...\left(1-\dfrac{1}{50.101}\right)\)
Bài 5. Tìm \(y\) biết:
a) \(\left(y+\dfrac{1}{2}\right)+\left(y+\dfrac{1}{4}\right)+\left(y+\dfrac{1}{8}\right)+\left(y+\dfrac{1}{16}\right)=1\)
b) \(\left(y+\dfrac{1}{2}\right)+\left(y+\dfrac{1}{4}\right)+\left(y+\dfrac{1}{8}\right)+...+\left(y+\dfrac{1}{1024}\right)=1\)
\(Tìm.x:\)
\(2x-\left(1+\dfrac{1}{1.3}\right).\left(1+\dfrac{1}{2.4}\right).\left(1+\dfrac{1}{3.5}\right)...\left(1+\dfrac{1}{2019+2021}\right)=x+1\)
ét o ét .-.
