Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\frac{5}{7}\).(\(\frac{1}{2}\)-\(\frac{1}{3}\)+\(\frac{4}{7}\)) +(\(\frac{1}{2}\)-\(\frac{1}{3}\)+\(\frac{4}{7}\)):\(\frac{7}{5}\)
= \(\frac{5}{7}\).(\(\frac{1}{2}\)-\(\frac{1}{3}\)+\(\frac{4}{7}\))+(\(\frac{1}{2}\)-\(\frac{1}{3}\)+\(\frac{4}{7}\)).\(\frac{5}{7}\)
=2.\(\frac{5}{7}\).(\(\frac{1}{2}\)-\(\frac{1}{3}\)+\(\frac{4}{7}\))
=\(\frac{10}{7}\).(\(\frac{21}{42}\)-\(\frac{8}{42}\)+\(\frac{24}{42}\))
=\(\frac{10}{7}\).\(\frac{37}{42}\)=\(\frac{185}{147}\)
\(5\dfrac{5}{11}-\left(2\dfrac{3}{5}\cdot4\dfrac{6}{11}\right)=\dfrac{60}{11}-\left(\dfrac{13}{5}\cdot\dfrac{50}{11}\right)=\dfrac{60}{11}-\dfrac{130}{11}=-\dfrac{70}{11}\)
a, \(\frac{3}{5}+\frac{-4}{15}=\frac{9}{15}-\frac{4}{15}=\frac{5}{15}=\frac{1}{3}\)
b, \(\frac{-1}{3}+\frac{2}{5}+\frac{2}{15}=\frac{-5}{15}+\frac{6}{15}+\frac{2}{15}=\frac{3}{15}=\frac{1}{5}\)
c, \(\frac{-3}{5}+\frac{7}{21}+\frac{-4}{5}+\frac{7}{5}=\frac{-3}{5}+\frac{1}{3}+\frac{-4}{5}+\frac{7}{5}=\left(\frac{-3}{5}+\frac{-4}{5}+\frac{7}{5}\right)+\frac{1}{3}=\frac{1}{3}\)
d, \(\frac{2}{7}+\frac{1}{9}+\frac{3}{7}+\frac{5}{9}+\frac{-5}{6}=\left(\frac{2}{7}+\frac{3}{7}\right)+\left(\frac{1}{9}+\frac{5}{9}\right)+\frac{-5}{6}=\frac{5}{7}+\frac{6}{9}+\frac{-5}{6}=\frac{90}{126}+\frac{84}{126}+\frac{-105}{126}=\frac{69}{126}=\frac{23}{42}\)
e, \(\frac{-5}{7}+\frac{3}{4}+\frac{-1}{5}+\frac{-2}{7}+\frac{1}{4}=\left(\frac{-5}{7}+\frac{-2}{7}\right)+\left(\frac{3}{4}+\frac{1}{4}\right)+\frac{-1}{5}=\left(-1\right)+1+\frac{-1}{5}=\frac{-1}{5}\)
f, \(\frac{-3}{31}+\frac{-6}{17}+\frac{1}{25}+\frac{-28}{31}+\frac{-1}{17}+\frac{-1}{5}=\left(\frac{-3}{31}+\frac{-28}{31}\right)+\left(\frac{-6}{17}+\frac{-1}{17}\right)+\left(\frac{1}{25}+\frac{-1}{5}\right)=\left(-1\right)+\frac{-7}{17}+\frac{-4}{25}=\frac{-425}{425}+\frac{-175}{425}+\frac{-68}{425}=\frac{-668}{425}\)
Chúc bn học tốt
3/7 *14/5 - 1/2 = 6/5-1/2 = 7/10
2/5 - 3/5 *5/10 = 2/5 - 3/10 = 1/10
4/13 *5/11 + 4/13 *6/11 - 4/13
= 4/13*5/11 +4/13 *6/11 - 4/13 *1
= 4/13 *(5/11+ 6/11 - 1)
= 4/13 *0
=0
\(\frac{5}{2.3}+\frac{5}{3.4}+\frac{5}{4.5}+...+\frac{5}{99.100}\)
\(=5.\left(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+....+\frac{1}{99.100}\right)\)
\(=5.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-....-\frac{1}{100}\right)\)
\(=5.\left(\frac{1}{2}-\frac{1}{100}\right)=\frac{5.49}{100}=\frac{49}{20}\)
5/2 . 3 + 5/3 .4+5/4 .5 +.......+5/99.100
= ( 1 / 2.3 + 1 /3.4 + 1 / 4.5 + ..... + 5 / 99. 100 ). 5
= 5 ( 1 / 2 - 1 / 3 + 1 / 3 - 1 / 4 + 1 / 4 - 1 / 5 +.... + 1 / 99 - 1 / 100 )
= 5 ( 1 / 2 - 1 / 100 )
= 5 . 49 / 100
= 49 / 20