a: \(A=\dfrac{15}{4}-\dfrac{9}{4}=\dfrac{6}{4}=\dfrac{3}{2}\)

b: \(B=\dfrac{-3}{2}\cdot\dfrac{7-5\cdot4}{3}=\dfrac{-13}{-2}=\dfrac{13}{2}\)

c: \(C=\dfrac{-21}{10}\left(1-\dfrac{3}{4}\right)-\dfrac{3}{4}\)

\(=\dfrac{-21}{10}\cdot\dfrac{1}{4}-\dfrac{3}{4}\)

\(=\dfrac{-21}{40}-\dfrac{30}{40}=\dfrac{-51}{40}000000997\)

d: \(D=\dfrac{-2}{3}+\dfrac{-12}{5}-3=\dfrac{-10-36-45}{15}=\dfrac{-91}{15}\)

a)(-0,25).4/17.(-3 5/21).(-7/12)

= -1/17 . (-68/21) . ( -7/21)

= -4/63

b) (-2/5).4/15+(-3/10).4/15

= 4/15. [-2/5 + (-3/10)]

= 4/15 . (-7/10)

= -14/75

c)21-3 3/4:(3/8-1/6)

= 21 - 15/4 : 5/24

= 21 - 18

= 3

d) (-3/4+2/5):3/7+(3/5+-1/4):3/7

= [(-3/4 + 2/5) + (3/5 + -1/4)] : 3/7

= [-7/20 + (-17/20)] : 3/7

= -6/5 : 3/7

= -14/5

a) Ta có: \(\dfrac{-5}{7}\left(\dfrac{14}{5}-\dfrac{7}{10}\right):\left|-\dfrac{2}{3}\right|-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)+\dfrac{10}{3}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\)

\(=\dfrac{-5}{7}\cdot\dfrac{3}{2}\cdot\dfrac{21}{10}-\dfrac{3}{4}\cdot\dfrac{56}{3}+\dfrac{10}{3}\cdot\dfrac{8}{15}\)

\(=\dfrac{-9}{4}-14+\dfrac{16}{9}\)

\(=\dfrac{-1621}{126}\)

b) Ta có: \(\dfrac{17}{-26}\cdot\left(\dfrac{1}{6}-\dfrac{5}{3}\right):\dfrac{17}{13}-\dfrac{20}{3}\left(\dfrac{2}{5}-\dfrac{1}{4}\right)+\dfrac{2}{3}\left(\dfrac{6}{5}-\dfrac{9}{2}\right)\)

\(=\dfrac{-17}{26}\cdot\dfrac{13}{17}\cdot\dfrac{-3}{2}-\dfrac{20}{3}\cdot\dfrac{3}{20}+\dfrac{2}{3}\cdot\dfrac{-33}{10}\)

\(=\dfrac{3}{4}-1-\dfrac{11}{5}\)

\(=-\dfrac{49}{20}\)

a; A = |-101| + |21| + |-99|  - |25|

   A = 101 + 21  + 99 - 25

 A = (101 + 99) - (25 - 21)

A = 200  -  4

A = 196 

b; B = ||17 - 42|  - 64|

    B = ||-25| - 64|

   B =  |25 - 64|

   B =  |-39|

  B = 39

c, C = |2⁷ - 7²| + |3³ - 3⁴| + |10³ - 3⁵|

   C = |128 - 49| + |27 - 81| + |1000 -  243|

   C = |79| + |-54| + | 757|

   C = 79 + 54 + 757

   C = 133 + 757

  C = 890 

d; D = |\(\dfrac{1}{3}\) - \(\dfrac{2}{3}\)| + |\(\dfrac{5}{6}\) + (-\(\dfrac{7}{12}\))|

    D = |-\(\dfrac{1}{3}\)|  + |\(\dfrac{1}{4}\)|

   D = \(\dfrac{1}{3}\) + \(\dfrac{1}{4}\)

   D  = \(\dfrac{7}{12}\)

`#` `\text{dkhanhqlv}`

`4)`

`a)3.(-5/11)`

`=-15/11`

`b)3/5+4/7 . 14/6`

`=3/5 + 4/3`

`=9/15+20/15`

`=29/15`

`c) 10/21-3/8 . 4/15`

`=10/21-1/10`

`=100/210-21/210`

`=79/100`

`d)(2/3+3/4)(5/7+5/14)`

`=(8/12+9/12)(10/14+5/14)`

`=17/12 . 15/14`

`=85/56`

`5)`

`a)x-1/2=3/10 . 5/6`

`=>x-1/2=1/4`

`=>x=1/4+1/2`

`=>x=1/4+2/4`

`=>x=3/4`

`b)x/5 = -3/14`

`=>x : 5 = -3/14`

`=>x=-3/14 . 5`

`=>x=-15/14`

`c)x+2/3=9/15 . 5/27`

`=>x+2/3=1/9`

`=>x=1/9-2/3`

`=>x=1/9-6/9`

`=>x=-5/9`

a: =-1/3+1/3=0

b: \(=\dfrac{4}{11}\left(-\dfrac{2}{7}-\dfrac{4}{7}-\dfrac{1}{7}\right)=\dfrac{4}{11}\cdot\left(-1\right)=-\dfrac{4}{11}\)

c: \(=10+\dfrac{5}{9}-3-\dfrac{5}{7}-4-\dfrac{5}{9}=3-\dfrac{5}{7}=\dfrac{16}{7}\)

d: \(=\dfrac{1}{3}+\dfrac{7}{4}-\dfrac{7}{4}+\dfrac{4}{5}=\dfrac{1}{3}+\dfrac{4}{5}=\dfrac{5+12}{15}=\dfrac{17}{15}\)

a: =-1/3+1/3=0

b: =10+59−3−57−4−59=3−57=167=10+59−3−57−4−59=3−57=167

d: 

12+3/7-11+3/7 tính bằng cách thuận tiện nhé

a) \(...=-\dfrac{1}{4}.\dfrac{4}{17}.\left(-\dfrac{63}{21}\right).\left(-\dfrac{7}{12}\right)\)

\(=-\dfrac{1}{17}.\dfrac{63}{21}.\dfrac{7}{12}\)

\(=-\dfrac{7}{68}\)

b) \(...=-\dfrac{2}{5}.\dfrac{4}{15}-\dfrac{3}{10}.\dfrac{4}{15}\)

\(=\dfrac{4}{15}\left(-\dfrac{2}{5}-\dfrac{3}{10}\right)\)

\(=\dfrac{4}{15}\left(-\dfrac{4}{10}-\dfrac{3}{10}\right)\)

\(=\dfrac{4}{15}.\left(-\dfrac{7}{10}\right)=-\dfrac{14}{75}\)

c) \(...=21-\dfrac{15}{4}:\left(\dfrac{9}{24}-\dfrac{4}{24}\right)\)

\(=21-\dfrac{15}{4}:\dfrac{5}{24}\)

\(=21-\dfrac{15}{4}.\dfrac{24}{5}\)

\(=21-3.6=3\)

d) \(...=\left(-\dfrac{3}{4}+\dfrac{2}{5}\right).\dfrac{7}{3}+\left(\dfrac{3}{5}-\dfrac{1}{4}\right).\dfrac{7}{3}\)

\(=\dfrac{7}{3}\left(-\dfrac{3}{4}+\dfrac{2}{5}+\dfrac{3}{5}-\dfrac{1}{4}\right)\)

\(=\dfrac{7}{3}\left(-\dfrac{3}{4}-\dfrac{1}{4}+\dfrac{2}{5}+\dfrac{3}{5}\right)\)

\(=\dfrac{7}{3}\left(-1+1\right)=0\)

a: \(C=\dfrac{-1}{2}:\dfrac{-2}{3}:\dfrac{-3}{4}\)

\(=\dfrac{-1}{2}\cdot\dfrac{3}{-2}\cdot\dfrac{4}{-3}\)

\(=-\dfrac{4}{4}=-1\)

b: \(D=\dfrac{-6}{5}:\dfrac{-5}{4}:\dfrac{-4}{3}\)

\(=-\dfrac{6}{5}\cdot\dfrac{4}{5}\cdot\dfrac{3}{4}\)

\(=\dfrac{-18}{25}\)

c: \(\dfrac{4}{20}+\dfrac{16}{42}+\dfrac{6}{15}+\dfrac{-3}{5}+\dfrac{2}{21}+\dfrac{-10}{21}+\dfrac{3}{20}\)

\(=\left(\dfrac{4}{20}+\dfrac{-3}{5}+\dfrac{6}{15}\right)+\left(\dfrac{16}{42}+\dfrac{2}{21}-\dfrac{10}{21}\right)+\dfrac{3}{20}\)

\(=\left(\dfrac{1}{5}-\dfrac{3}{5}+\dfrac{2}{5}\right)+\left(\dfrac{8}{21}+\dfrac{2}{21}-\dfrac{10}{21}\right)+\dfrac{3}{20}\)

\(=\dfrac{3}{20}\)

d: \(\dfrac{42}{46}+\dfrac{250}{186}+\dfrac{-2121}{2323}+\dfrac{-125125}{143143}\)

\(=\dfrac{21}{23}+\dfrac{125}{93}+\dfrac{-21}{21}+\dfrac{-125}{143}\)

\(=\dfrac{125}{93}-\dfrac{125}{143}=\dfrac{6250}{13299}\)