Chương I : Số hữu tỉ. Số thực

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\(=3\cdot\left[\dfrac{5}{6}-\dfrac{1}{5}:\dfrac{2+5}{20}\right]\)

\(=3\cdot\left[\dfrac{5}{6}-\dfrac{1}{5}\cdot\dfrac{20}{7}\right]\)

\(=3\cdot\left[\dfrac{5}{6}-\dfrac{4}{7}\right]=3\cdot\dfrac{35-24}{42}=\dfrac{11}{14}\)

=3⋅[56−15⋅207]=3⋅[56−15⋅207]

\(\Leftrightarrow\dfrac{x+2016}{5}-\dfrac{x+2016}{3}=\dfrac{x+2016}{2}\)

=>x+2016=0

=>x=-2016

Chọn A

Mình nghĩ chọn B . Kiểm tra coi mik làm đúng ko nhé

\(\dfrac{4}{11}.\dfrac{7}{13}+\dfrac{4}{11}:\dfrac{13}{6}-\dfrac{26}{11}=\dfrac{4}{11}.\dfrac{7}{13}+\dfrac{4}{11}.\dfrac{6}{13}-\dfrac{26}{11}\)

\(=\dfrac{4}{11}.\left(\dfrac{7}{13}+\dfrac{6}{13}\right)-\dfrac{26}{11}\)

\(=\dfrac{4}{11}-\dfrac{26}{11}\)

\(=-\dfrac{22}{11}\)

\(=-2\)

`4/11 . 7/13 + 4/11 : 13/6 - 26/11 `

`= 4/11 . 7/13 + 4/11 xx 6/13 - 26/11 `

`= 4/11 . ( 7/13+6/13)-26/11`

`= 4/11. 1-26/11`

`= 4/11 - 26/11`

`=-22/11=-2`

A: -0,5

B: -0,35

C: -0,15

\(\dfrac{7}{12}:\left(-6\right)-\left[-5\dfrac{5}{6}:\left(-3\dfrac{2}{9}\right)\right]\)

=\(\dfrac{-7}{72}-\dfrac{105}{58}\)

=-1,90756705

`7/12 : (-6) - [-5 5/6 : (-3 2/9 ) ]`

`= 7/12 xx (-1/6) + [ 5  5/6 : (-3 2/9 ) ]`

`= -7/72 + [ 35/6 : (-29/9 )]`

`= -7/72 + [ 35/6 xx (-9/29) ]`

`= -7/72 + ( -315/174 )`

`= -7/72 + ( -105/58 )`

`= -406/4176 + ( -7560/4176 )`

`= -7966/4176`

`= -3938/2088`

`#C_n`

Câu 2: 

a: \(\left|-37\right|=37\)

b: \(=\left|-\dfrac{3}{11}\right|=\dfrac{3}{11}\)

c: =17,07

d: căn 13

Bài 3: 

a: -3,8(3)<-3,832

b: \(\dfrac{3}{7}>0.4285\)

nên \(2\dfrac{3}{7}>2.4285\)

c: 13<15

nên căn 13<căn 15

a,\(\dfrac{2}{3}x-\dfrac{3}{4}x=\left(-\dfrac{5}{12}\right).\dfrac{8}{15}\)

\(\left(\dfrac{2}{3}-\dfrac{3}{4}\right)x=\dfrac{-2}{9}\)

\(\dfrac{1}{6}x=\dfrac{-2}{9}\)

\(x=\dfrac{-2}{9}:\dfrac{1}{6}\)

\(x=\dfrac{-4}{3}\)

Vậy x=\(\dfrac{-4}{3}\)

b,\(\left(2:x-\dfrac{3}{5}\right)^2=16\)

\(\left(2:x-\dfrac{3}{5}\right)^2=4^2\)

\(2:x-\dfrac{3}{5}=4\)

\(2:x=4+\dfrac{3}{5}\)

\(2:x=\dfrac{23}{5}\)

\(x=\dfrac{23}{5}:2\)

\(x=\dfrac{23}{10}\)

Vậy \(x=\dfrac{23}{10}\)

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Bài 2: 

a: =>2/5-3:x=3 hoặc 2/5-3:x=-3

=>3:x=2/5-3=-13/5 hoặc 3:x=2/5+3=17/5

=>x=-3:13/5=-15/13 hoặc x=3:17/5=15/17

b: =>4/15x=-5/12*4/15=-20/180=-1/9

=>x=-1/9:4/15=-1/9*15/4=-15/36=-5/12

a,\(\left(\dfrac{2}{5}-3:x\right)^2=9\)

\(\left(\dfrac{2}{5}-3:x\right)=3^2\)

\(\dfrac{2}{5}-3:x=3\)

\(3:x=\dfrac{2}{5}-3\)

\(3:x=\dfrac{-13}{5}\)

x=\(3:\dfrac{-13}{5}\)

x=\(\dfrac{-15}{13}\)

Vậy x=\(\dfrac{-15}{13}\)

b,\(\dfrac{2}{3}x-\dfrac{2}{5}x=\left(\dfrac{-5}{12}\right).\dfrac{4}{15}\)

\(\left(\dfrac{2}{3}-\dfrac{2}{5}\right)x=\dfrac{-1}{9}\)

\(\dfrac{4}{15}x=\dfrac{-1}{9}\)

x=\(\dfrac{-1}{9}:\dfrac{4}{15}\)

x=\(\dfrac{-5}{12}\)

Vậy x=\(\dfrac{-5}{12}\)