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3 tháng 7 2017

\(\left(\dfrac{9}{25}-2.8\right):\left(\dfrac{19}{5}+0.2\right)\)

\(=\left(\dfrac{9}{25}-\dfrac{14}{5}\right):\left(\dfrac{19}{5}+\dfrac{1}{5}\right)\)

\(=\left(\dfrac{9-70}{25}\right):4\)

\(=\dfrac{-61}{25}:4=\dfrac{-61}{25}.\dfrac{1}{4}\)

\(=-\dfrac{61}{100}\)

3 tháng 7 2017

\(\left(\dfrac{9}{25}-2.18\right):\left(\dfrac{19}{5}+0,2\right)\)

\(=\left(\dfrac{9}{25}-36\right):\left(\dfrac{19}{5}+0,2\right)\)

\(=\dfrac{-891}{25}:4=\dfrac{-891}{100}\)

23 tháng 3 2022

\(\dfrac{5}{3}\cdot\dfrac{7}{25}+\dfrac{5}{3}\cdot\dfrac{21}{25}-\dfrac{5}{3}\cdot\dfrac{7}{25}\)

\(=\dfrac{5}{3}\cdot\left(\dfrac{7.}{25}+\dfrac{21}{25}-\dfrac{7}{25}\right)\)

\(=\dfrac{5}{3}\cdot\dfrac{21}{25}=\dfrac{7}{5}\)

b) \(250\%+19\dfrac{3}{11}\cdot\dfrac{7}{26}-6\dfrac{3}{11}\cdot\dfrac{7}{26}\)

\(=\dfrac{5}{2}+\dfrac{212}{11}\cdot\dfrac{7}{26}-\dfrac{69}{11}\cdot\dfrac{7}{26}\)

\(=\dfrac{7}{26}\cdot\left(\dfrac{212}{11}-\dfrac{69}{11}\right)+\dfrac{5}{2}\)

\(=\dfrac{7}{26}\cdot13+\dfrac{5}{2}\)

\(=\dfrac{7}{2}+\dfrac{5}{2}\)

\(=\dfrac{12}{2}=6\)

 

1 tháng 2 2017

(1-3)+(5-7)+(9-11)+....+(17-19)

=(-2)+(-2)+(-2)+...+(-2)

=(-2)x5

=-10

10 tháng 3 2023

\(\dfrac{4}{5}\)+\(\dfrac{-5}{4}\)=\(\dfrac{0}{4}\)

\(\dfrac{-1}{3}\)+\(\dfrac{2}{5}-\dfrac{5}{6}\)=\(\dfrac{-10}{30}+\dfrac{12}{30}-\dfrac{25}{30}\)=\(\dfrac{-23}{30}\)

\(\dfrac{2}{3}-\dfrac{5}{7}.\dfrac{14}{25}\)=\(\dfrac{2}{3}-\dfrac{2}{5}\)=\(\dfrac{10}{15}-\dfrac{6}{15}\)=\(\dfrac{4}{15}\)

 

10 tháng 3 2023

Gigachad cảm ơn bạn sai rồi

 

11 tháng 5 2018

\(\frac{5}{19}-\frac{19}{5}-\frac{27}{43}+\frac{14}{19}-\frac{16}{43}\)

\(=\left(\frac{5}{19}+\frac{14}{19}\right)+\left(\frac{-27}{43}-\frac{16}{43}\right)-\frac{19}{5}\)

\(=1-1=0\)

a: \(=32+140:70-49=32+2-49=34-49=-15\)

b: \(=408-\left[20:4+9\right]:2=408-7=401\)

c: \(=-564-724+564+224=-500\)

22 tháng 11 2023

a) \(31\cdot72+\left(-31\right)\cdot70-2\cdot70\)

\(=31\cdot72-31\cdot70-2\cdot70\)

\(=31\cdot\left(72-70\right)-2\cdot70\)

\(=31\cdot2-2\cdot70\)

\(=2\cdot\left(31-70\right)\)

\(=2\cdot-39\)

\(=-78\) 

b) \(25\cdot\left(32+17\right)-32\cdot\left(25+47\right)\)

\(=25\cdot32+25\cdot17-32\cdot25-32\cdot47\) 

\(=25\cdot\left(32-32+17\right)-32\cdot47\)

\(=25\cdot17-32\cdot47\)

\(=425-1504\)

\(=-1079\)

30 tháng 11 2023

a: \(-472+\left(235-28\right)-\left(35-350\right)\)

\(=-472+235-28-35+350\)

\(=\left(-472-28\right)+\left(235-35\right)+350\)

=-500+350+200

=50

b: \(91\cdot172+91\cdot13-91\cdot85\)

\(=91\cdot\left(172+13-85\right)\)

\(=91\cdot100=9100\)

c: \(798-298:\left[19-2\left(5^2-22\right)^2\right]\cdot1^{2023}\)

\(=798-298:\left[19-2\left(25-22\right)^2\right]\)

\(=798-298:\left[19-2\cdot3^2\right]\)

\(=798-298:\left(19-18\right)\)

=798-298

=500

30 tháng 11 2023

E cảm ơn ạ 👍