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13 tháng 5 2018

 \(\frac{13}{25}+\frac{6}{41}-\frac{38}{25}+\frac{35}{41}-\frac{1}{2}\) 

\(=\left(\frac{13}{25}-\frac{38}{25}\right)+\left(\frac{6}{41}+\frac{35}{41}\right)-\frac{1}{2}\) 

\(=-1+1-\frac{1}{2}=0-\frac{1}{2}\) 

\(=\frac{-1}{2}\) 

\(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\) 

\(=\left(1\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+0,5\) 

\(=1+1+0,5=2,5\)

13 tháng 5 2018

\(\frac{13}{25}+\frac{4}{41}-\frac{38}{25}+\frac{35}{41}-\frac{1}{2}\)

\(\left(\frac{13}{25}-\frac{38}{25}\right)+\left(\frac{6}{41}+\frac{35}{41}\right)-\frac{1}{2}\)

\(-1+1-\frac{1}{2}=-\frac{1}{2}\)

\(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)

=\(\left(1\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+0,5\)

\(1+1+0,5=2,5\)

15 tháng 12 2022

a: \(=\dfrac{5}{4}\cdot\dfrac{2}{5}\cdot\dfrac{17}{21}\cdot\dfrac{7}{34}=\dfrac{1}{2}\cdot\dfrac{1}{2}\cdot\dfrac{1}{3}=\dfrac{1}{12}\)

b: =>0,5^x(0,5+1)=1,5

=>0,5^x=1

=>x=0

c: =>x*0,05-0,25*x=-1,2

=>-0,3*x=-1,2

=>x=4

d: =>x-1=1 hoặc x-1=-1

=>x=0 hoặc x=2

e: =5+4=9

8 tháng 5 2022

`21/25-5/21-[-4]/25-16/21+1/2`

`=(21/25-[-4]/25)-(5/21+16/21)+1/2`

`=25/25-21/21+1/2`

`=1-1+1/2=1/2`

a: \(=\dfrac{5}{6}\cdot\dfrac{-12}{7}=\dfrac{-10}{7}\)

b: \(=\dfrac{7}{8}\cdot\dfrac{8}{14}=\dfrac{7}{14}=\dfrac{1}{2}\)

c: \(=\dfrac{4}{5}\cdot\dfrac{-15}{8}=\dfrac{-3}{2}\)

d: \(=\dfrac{15}{16}\cdot\dfrac{8}{25}=\dfrac{15}{25}\cdot\dfrac{1}{2}=\dfrac{3}{5}\cdot\dfrac{1}{2}=\dfrac{3}{10}\)

đ: \(=\dfrac{2}{3}-\dfrac{70}{175}=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{10-6}{15}=\dfrac{4}{15}\)

9 tháng 8 2017

a) \(\dfrac{7}{-25}+\dfrac{8}{25}=\dfrac{-7}{25}+\dfrac{8}{25}=\dfrac{1}{25}\)

\(\dfrac{4}{5}+\dfrac{4}{-18}=\dfrac{4}{5+\left(-18\right)}=\dfrac{4}{-13}=\dfrac{-4}{13}\)

\(\dfrac{7}{21}+\dfrac{9}{-36}=\dfrac{1}{3}+\dfrac{1}{-4}=\dfrac{1}{3+\left(-4\right)}=\dfrac{1}{-1}=1\)

b) \(\dfrac{12}{20}-\dfrac{2}{5}=\dfrac{12}{20}+\left(\dfrac{-2}{5}\right)=\dfrac{3}{5}+\dfrac{-2}{5}=\dfrac{3+\left(-2\right)}{5}=\dfrac{1}{5}\)

\(\dfrac{2}{3}-\dfrac{-5}{6}=\dfrac{2}{3}+\dfrac{5}{6}=\dfrac{4}{6}+\dfrac{5}{6}=\dfrac{9}{6}=\dfrac{3}{2}\)

\(6-\dfrac{3}{20}=6+\dfrac{-3}{20}=\dfrac{60}{60}+\dfrac{-9}{60}=\dfrac{51}{60}\)

c) \(\dfrac{2}{21}.\dfrac{-7}{3}=\dfrac{2.\left(-1\right)}{7.3}=\dfrac{-2}{21}\)

\(\dfrac{27}{28}.\left(-21\right)=\dfrac{27.\left(-21\right)}{28}=\dfrac{-567}{28}\)

\(\dfrac{-15}{7}.\dfrac{-14}{25}=\dfrac{-3.\left(-2\right)}{1.5}=\dfrac{6}{5}\)

3 tháng 11 2019

(-3/4+2/3):5/11+(-1/4+1/3):5/11

15 tháng 6 2020

a)|x-13|-35-45=-47

b)(4+x).(x+3)=0

c)25-(5-x)=120-(28-5)

a: \(=3\cdot\left(\dfrac{1}{4}-\dfrac{6}{7}+\dfrac{8}{21}\right)\)

\(=3\cdot\left(\dfrac{21}{84}-\dfrac{72}{84}+\dfrac{32}{84}\right)\)

\(=\dfrac{-19}{28}\)

b: \(=\dfrac{-2}{3}\left(\dfrac{1}{9}-\dfrac{1}{6}-\dfrac{1}{11}\right)\)

\(=\dfrac{-2}{3}\cdot\dfrac{-29}{198}=\dfrac{29}{99\cdot3}=\dfrac{29}{297}\)

c: \(=\dfrac{-3}{7}+\dfrac{4}{25}+\dfrac{5}{16}+\dfrac{3}{16}\)

\(=\dfrac{-75+28}{175}+\dfrac{1}{2}\)

\(=\dfrac{-47}{175}+\dfrac{1}{2}=\dfrac{-94+175}{350}=\dfrac{81}{350}\)

d: \(=\dfrac{-4}{9}\cdot\left(\dfrac{1}{26}-\dfrac{1}{2}-\dfrac{1}{8}\right)\)

\(=\dfrac{-4}{9}\cdot\dfrac{-61}{104}=\dfrac{61}{26\cdot9}=\dfrac{61}{234}\)