a) \(\dfrac{2.3+4.6+14.21}{3.5+6.10+21.35}=\dfrac{2.3\left(1+2.2+7.7\right)}{3.5\left(1+2.2+7.7\right)}=\dfrac{2}{5}\)
b) \(\dfrac{-1997.1996+1}{\left(-1995\right)\left(-1997\right)+1996}=\dfrac{-1997\left(1995+1\right)+1}{1995.1997+1996}=\dfrac{-1997.1995+\left(-1997\right)+1}{1995.1997+1996}=\dfrac{-1997.1995+\left(-1996\right)}{1995.1997+1996}=-1\)
Rút gọn phân số:
a/ 25.13/26.35
b/ 6.9 - 2.17/63.3 - 119
c/ 3.13 - 13.18/15.40 - 80
d/ 2929 - 101/2.1919 + 404
f/ -1997.1996+1/(-1995).(-1997)+1996
g/ 2.3+4.6+14.21/ 3.5+6.10+21.35
h/ 3.7.13.37.39 - 10101/ 505050 - 70707
/ dấu phân số
1,Rút gọn phân số:
a, \(\frac{-315}{540}\)
b,\(\frac{25.13}{26.35}\)
c,\(\frac{2929-101}{2.1919+404}\)
d,\(\frac{-1997.1996+1}{\left(1995\right).\left(-1997\right)+1996}\)
rút gọn p/s:
a,\(\dfrac{18.34+\left(-18\right).124}{-36.17+9.\left(-52\right)}\)
b, \(\dfrac{3.7.13.37.39-10101}{505050-70707}\)
Help me
\(\left(1+\dfrac{2}{2.3}\right).\left(1+\dfrac{2}{3.4}\right).....\left(1+\dfrac{2}{n\left(n+1\right)}\right)\)
\(\left(1+\dfrac{1}{1.3}\right)\left(1+\dfrac{1}{2.4}\right)\left(1+\dfrac{1}{3.5}\right)...\left(1+\dfrac{1}{2016.2018}\right)\)
MỌI NGƯỜI GIÚP MÌNH VỚI!!! 
Tìm số tự nhiên x
a) \(\dfrac{x}{2008}-\dfrac{1}{10}-\dfrac{1}{15}-\dfrac{1}{21}-....-\dfrac{1}{120}=\dfrac{5}{8}\)
b)\(\dfrac{1}{3.5}+\dfrac{1}{5.7}+\dfrac{1}{7.9}+....+\dfrac{1}{\left(2x+1\right).\left(2x+3\right)}=\dfrac{15}{93}\)
rút gọn p/s
a, \(\dfrac{2929-101}{2.1919+404}\)
b, \(\dfrac{\left(-5\right)^3.40.4^3}{135.\left(-2\right)^{14}.\left(-100\right)^0}\)
\(\dfrac{0,8:\left(\dfrac{4}{5}.1,25\right)}{0,64-\dfrac{1}{25}}\)+\(\dfrac{\left(100-\dfrac{2}{5}\right):\dfrac{4}{7}}{6.\left(\dfrac{5}{9}-3\dfrac{1}{4}\right).2\dfrac{2}{17}}\)
help me, please
Nhanh lên nha, mai mình đi học rùi
Thank you so much
Chứng minh rằng với mọi \(n\in N\); \(n\ge2\) ta có :
\(\dfrac{3}{9.14}+\dfrac{3}{14.19}+\dfrac{3}{19.24}+..........+\dfrac{3}{\left(5n-1\right)\left(5n+4\right)}< \dfrac{1}{15}\)
Help me!!!!!!!!!!!!!!!!!!
