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16 tháng 9 2021

\(A=\dfrac{2}{3}+\dfrac{-1}{3}=\dfrac{1}{3}\\ B=\dfrac{25}{11}\times\dfrac{13}{12}\times\dfrac{-11}{5}=\dfrac{5\times13\times\left(-1\right)}{1\times12\times1}=\dfrac{-65}{12}\\ C=\left(\dfrac{3}{4}-\dfrac{1}{5}\right)\times\left(\dfrac{2}{5}-\dfrac{4}{5}\right)=\dfrac{11}{20}\times\dfrac{-2}{5}=\dfrac{-11}{50}\)

\(B< -1< C< 0< A\\ \Leftrightarrow B< C< A\)

9 tháng 6 2017

Sau khi thực hiện phép tính ta được kết quả các giá trị:

\(A=\dfrac{1}{3}\) \(B=-5\dfrac{5}{12}\) \(C=-0,22\)

Sắp xếp: \(-5\dfrac{5}{12}< -0,22< \dfrac{1}{3}\) tức là \(B< C< A\)

28 tháng 8 2017

Khi tính xong giá trị biểu thức A , B và C ta được kết quả như sau :

\(A=\dfrac{1}{3}\) ; \(B=-5\dfrac{5}{12}\); \(C=-0,22\)

Sắp xếp : \(B< C< A\)\(\left(-5\dfrac{5}{12}< -0,22< \dfrac{1}{3}\right)\)

4 tháng 9 2018

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

\(A=\dfrac{5}{4}.\dfrac{11}{3}.\left(-\dfrac{1}{11}\right)\)

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

\(B=\dfrac{3}{4}:\left(-12\right).\left(-\dfrac{2}{3}\right)\)

\(B=\dfrac{3}{4}.\left(-\dfrac{1}{12}\right).\left(-\dfrac{2}{3}\right)\)

\(B=\dfrac{1}{24}\)

\(C=\dfrac{5}{4}:\left(-15\right).\left(-\dfrac{2}{5}\right)\)

\(C=\dfrac{5}{4}.\left(-\dfrac{1}{15}\right).\left(-\dfrac{2}{5}\right)\)

\(C=\dfrac{1}{30}\)

\(D=\left(-3\right)\left(\dfrac{2}{3}-\dfrac{5}{4}\right):\left(-7\right)\)

\(D=\left(-3\right)\left(-\dfrac{7}{12}\right)\left(-\dfrac{1}{7}\right)\)

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

Sắp xếp theo thứ tự tăng dần:

\(A,D,C,B\)

14 tháng 9 2017

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

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

=\(\dfrac{5}{4}\).[\(\dfrac{11}{3}.\left(-\dfrac{1}{11}\right)\text{]}\)

=\(\dfrac{5}{4}.\dfrac{1}{3}\)

=\(\dfrac{5}{12}\) (1)

B=\(\dfrac{3}{4}:\left(-12\right).\left(-\dfrac{2}{3}\right)\) =\(\dfrac{3}{4}:\text{[}\left(-12\right).\left(-\dfrac{2}{3}\right)\text{]}\)

=\(\dfrac{3}{4}:8\) =\(\dfrac{3}{4}.\dfrac{1}{8}\)=\(\dfrac{3}{32}\)(2)

C=\(\dfrac{5}{4}:\left(-15\right).\left(-\dfrac{2}{5}\right)\) =\(\dfrac{5}{4}:\text{[}\left(-15\right).\left(-\dfrac{2}{5}\right)\text{]}\)

=\(\dfrac{5}{4}:6=\dfrac{5}{4}.\dfrac{1}{6}=\dfrac{5}{24}\left(3\right)\)

D=(-3).\(\left(\dfrac{2}{3}-\dfrac{5}{4}\right):\left(-7\right)\) =(-3).\(\left(-\dfrac{7}{12}\right)\):(-7)=\(\dfrac{7}{4}:\left(-7\right)\)=\(\dfrac{7}{4}\).\(\left(\dfrac{-1}{7}\right)\)=\(\dfrac{-1}{4}\) (4)

Từ (1),(2),(3)và(4)=>Ta có thể sắp xếp các kết quả trên theo thứ tự tăng dần là:

(Bạn tự làm nhé! mình bận đi học rồileuleu)

\(A=\dfrac{5}{4}\cdot\dfrac{15-4}{3}\cdot\dfrac{-1}{11}=\dfrac{5}{4}\cdot\dfrac{11}{3}\cdot\dfrac{-1}{11}=\dfrac{-5}{12}\)=-50/120

\(B=\dfrac{3}{4}\cdot\dfrac{-1}{12}\cdot\dfrac{-2}{3}=\dfrac{3\cdot2}{4\cdot12\cdot3}=\dfrac{2}{4\cdot12}=\dfrac{1}{24}\)=5/120

\(C=\dfrac{5}{4}\cdot\dfrac{-1}{15}\cdot\dfrac{-2}{5}=\dfrac{2}{4\cdot15}=\dfrac{1}{30}\)=4/120

\(D=3\cdot\dfrac{8-15}{12}\cdot\dfrac{-1}{7}=\dfrac{1}{4}\)=30/120

Vì -50<4<5<30

nên A<C<B<D

Vì A= \(\frac{605}{36}\)

B=\(\frac{-1}{24}\)

C=\(\frac{-1}{30}\)

D= \(\frac{-1}{4}\)

tức là  : A= \(\frac{6050}{360}\)

B=\(\frac{-15}{360}\)

C=\(\frac{-12}{360}\)

D=\(\frac{-90}{360}\)

nÊN được sắp xếp theo thứ tự tăng dần là B < C  < D < A

D=

25 tháng 10 2018

\(a,-\dfrac{3}{5}.y=\dfrac{21}{10}\)

\(y=\dfrac{21}{10}:\dfrac{-3}{5}=\dfrac{-7}{2}\)

\(b,y:\dfrac{3}{8}=-1\dfrac{31}{33}\)

\(y=-1\dfrac{31}{33}.\dfrac{3}{8}=\dfrac{-8}{11}\)

Vậy \(y=-\dfrac{8}{11}\)

\(c,1\dfrac{2}{5}.y+\dfrac{3}{7}=-\dfrac{4}{5}\)

\(\Rightarrow1\dfrac{2}{5}y=-\dfrac{4}{5}-\dfrac{3}{7}=\dfrac{-43}{35}\)

\(\Rightarrow y=\dfrac{-43}{35}:1\dfrac{2}{5}=\dfrac{-43}{49}\)

\(d,-\dfrac{11}{12}.y+0,25=\dfrac{5}{6}\)

\(\Rightarrow-\dfrac{11}{12}.y=\dfrac{5}{6}-0,25=\dfrac{7}{12}\)

\(\Rightarrow y=\dfrac{7}{12}:\dfrac{-11}{12}=\dfrac{-7}{11}\)

19 tháng 8 2016

\(A=\frac{1}{3}\)

\(B=\frac{25}{11}.\frac{13}{12}.\left(-2,2\right)=\frac{-65}{12}\)

\(C=\frac{11}{20}.\left(-\frac{2}{5}\right)=-\frac{11}{50}\)

tự sắp xếp nha

19 tháng 8 2016

A= 2/3 +3/4  . -4/9

  = 2/3 - 1/3

  = 1/3

B=\(2\frac{3}{11}.1\frac{1}{12}.\left(-2,2\right)\)

  = 25/11.13/12.-11/5

  = (25/11.-11/5).13/12

  = -5 . 13/12

  = -65/12

C= (3/4-0,2)(0,4-4/5)

  = (0,75 - 0,2)( 0,4 - 0,8)

  = 0,55 . -0,4

  = -0,22 = -11/50

Ta có: A= 1/3 ; B=-65/12 ; C= -11/50

=> -65/12 < -11/50 < 0 

Mà 1/3 > 0 => -65/ 12 < -11/50 < 1/3

Vậy b<c<a

23 tháng 9 2018

I , tìm x :

a, \(\left|x\right|=1,21\)

Ta có : \(\left|x\right|=\left|1,21\right|\rightarrow\left|x\right|=\pm1,21\)

b, \(\dfrac{11}{12}-\left(\dfrac{2}{5}-x\right)=\dfrac{2}{3}\)

\(\dfrac{2}{5}-x=\dfrac{11}{12}-\dfrac{2}{3}\)

\(\dfrac{2}{5}-x=\dfrac{1}{4}\) => \(x=\dfrac{2}{5}-\dfrac{1}{4}\)

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

c, \(\dfrac{3}{4}+\dfrac{1}{4}:x=\dfrac{2}{5}\)

\(\dfrac{1}{4}\div x=\dfrac{2}{5}-\dfrac{3}{4}\)

\(\dfrac{1}{4}\div x=\dfrac{-7}{20}\) => \(x=\dfrac{1}{4}\div\dfrac{-7}{20}\)

=> \(x=\dfrac{-5}{7}\)

d,\(3^x=81\)

Ta có 81= \(3^4\)

Vì : \(3^x=3^4\Rightarrow x=4\)

e,\(\dfrac{1}{2}.\left|x\right|-\dfrac{5}{2}=\dfrac{8}{3}\)

\(\left|x\right|-\dfrac{5}{6}=\dfrac{8}{3}:\dfrac{1}{2}\)

=> \(\left|x\right|-\dfrac{5}{2}=\dfrac{16}{3}\) => \(\left|x\right|=\dfrac{16}{3}+\dfrac{5}{2}\)

=> \(\left|x\right|=\dfrac{47}{6}\)

\(\left|x\right|=\left|\dfrac{47}{6}\right|\Rightarrow x=\pm\dfrac{47}{6}\)

f, \(2^{x-3}=4\)

\(2^{x-3}=2^2\)

=> \(x-3=2\)

=> \(x=5\)

23 tháng 9 2018

a, Ta có \(\left|x\right|=1,21\)

\(\Rightarrow\left[{}\begin{matrix}x=1,21\\x=-1,21\end{matrix}\right.\)

Vậy \(x\in\left\{1,21;-1,21\right\}\)

a: \(=5-2\cdot\dfrac{1}{4}=5-\dfrac{1}{2}=\dfrac{9}{2}\)

b: \(=\left(\dfrac{7}{2}\right)^3+\dfrac{1}{2}=\dfrac{343}{8}+\dfrac{1}{2}=\dfrac{347}{8}\)

c: \(=\left(5+\dfrac{5}{27}-\dfrac{5}{27}\right)+\left(\dfrac{7}{23}+\dfrac{16}{23}\right)-\dfrac{1}{2}=5+1-\dfrac{1}{2}=5+\dfrac{1}{2}=5.5\)

e: \(=\dfrac{-5}{4}\left(35+\dfrac{1}{6}-45-\dfrac{1}{6}\right)=\dfrac{-5}{4}\cdot\left(-10\right)=\dfrac{50}{4}=\dfrac{25}{2}\)

1: \(A=\dfrac{-25}{27}-\dfrac{31}{42}+\dfrac{7}{27}+\dfrac{3}{42}=\dfrac{-2}{3}-\dfrac{2}{3}=\dfrac{-4}{3}\)

2: \(B=\dfrac{10.3-\left(9.5-4.5\right)\cdot2}{1.2-1.5}=\dfrac{10.3-10}{-0.3}=-1\)

c: \(=\dfrac{3}{49}\left(\dfrac{19}{2}-\dfrac{5}{2}\right)-\left(\dfrac{1}{20}-\dfrac{5}{20}\right)^2\cdot\left(\dfrac{-7}{14}-\dfrac{193}{14}\right)\)

\(=\dfrac{3}{49}\cdot7-\dfrac{1}{25}\cdot\dfrac{-200}{14}\)

\(=\dfrac{3}{7}+\dfrac{8}{14}=1\)