(-5/24+0,75+7/12).(-2 1/4)

=(-5/24+3/4+7/12).(-9/4)

=9/8.(-9/4)

=-81/32

\(\left(\dfrac{-5}{24}+0,75+\dfrac{7}{12}\right):\left(-2\dfrac{1}{4}\right)\\ =\left(\dfrac{-5}{24}+\dfrac{3}{4}+\dfrac{7}{12}\right):\dfrac{-9}{4}\\ =\dfrac{9}{8}.\dfrac{-4}{9}\\ =\dfrac{-1}{2}\)

a)\(\left(\frac{3}{4}+\frac{-7}{2}\right).\left(\frac{10}{11}+\frac{2}{22}\right)\)

\(\left(\frac{3}{4}+\frac{-14}{4}\right).\left(\frac{20}{22}+\frac{2}{22}\right)\)

\(\frac{-11}{4}.1=\frac{-11}{4}\)

câu b mk hiểu đề

0,75+7/12 chứ không phải = đâu

A = - 2 / 5 + ( - 2 / 5 + 2 )

A = - 2 / 5 + 8 / 5

A = 6 / 5

B = ( - 5 / 24 + 0, 75 + 7 / 12 ) : - 17/8

B = 9 / 8 : - 17/8

B = -9 / 17

C = 3 / 7 + ( - 1 / 5 + - 3 / 7 )

C = 3 / 7 - 1 / 5 - 3 / 7 

C = - 1 / 5 

D = ( 6 - 14 / 5 ) . 25 / 8 - 8 / 5 : 1 / 4 

D = 16 / 5 . 25 / 8 - 8 / 5 . 4 

D = 10 - 6 , 4 

D = 3,6

\(A=-\frac{2}{5}+\left[\left(-\frac{2}{5}\right)+2\right]=\left[\left(-\frac{2}{5}\right)+\left(-\frac{2}{5}\right)\right]+2=\left(-\frac{4}{5}\right)+2=\left(-\frac{4}{5}\right)+\frac{10}{5}=\frac{6}{5}\)\(\frac{10}{5}=\frac{6}{5}\)

\(B=\left[\left(-\frac{5}{24}\right)+0,75+\frac{7}{12}\right]:\left(\frac{-17}{8}\right)\)\(=\left[\left(-\frac{5}{24}\right)+\frac{3}{4}+\frac{7}{12}\right].\frac{-8}{17}\)

   \(=\left[\left(-\frac{5}{24}\right)+\frac{18}{24}+\frac{14}{24}\right].\frac{-8}{17}\)\(=\frac{27}{24}.\frac{-8}{17}=\frac{9}{8}.\frac{-8}{17}=\frac{9.\left(-8\right)}{8.17}=\frac{-9}{17}\)

\(C=\frac{3}{7}+\left[\left(-\frac{1}{5}\right)+\left(-\frac{3}{7}\right)\right]=\left[\frac{3}{7}+\left(-\frac{3}{7}\right)\right]+\left(-\frac{1}{5}\right)=-\frac{1}{5}\)

\(D=\left(6-\frac{14}{5}\right).\frac{25}{8}-\frac{8}{5}:\frac{1}{4}=\left(\frac{30}{5}-\frac{14}{5}\right).\frac{25}{8}-\frac{8}{5}.4\)

\(=\frac{16}{5}.\frac{25}{8}-\frac{32}{5}=\frac{16.25}{5.8}-\frac{32}{5}=10-\frac{32}{5}\)\(=\frac{50}{5}-\frac{32}{5}=\frac{18}{5}\)

Bài 1: 

1: =-5/24+16/27+3/4

=-5/24+18/24+16/27

=13/24+16/27

=117/216+128/216=245/216

2: =-1/3+1/3+6/7=6/7

3: \(=\dfrac{1}{2}-\dfrac{7}{12}+\dfrac{1}{2}=1-\dfrac{7}{12}=\dfrac{5}{12}\)

4: \(=-\dfrac{5}{8}+\dfrac{14}{25}-\dfrac{6}{10}=\dfrac{-125+112-120}{200}=\dfrac{-133}{200}\)

\(\left(\dfrac{7-5}{24}+0.75+\dfrac{7}{12}\right):\left(-2\dfrac{1}{8}\right)\)

\(=\left(\dfrac{1}{12}+\dfrac{3}{4}+\dfrac{7}{12}\right):\dfrac{-17}{8}\)

\(=\left(\dfrac{1}{12}+\dfrac{9}{12}+\dfrac{7}{12}\right):\dfrac{-17}{8}\)

\(=\dfrac{17}{12}:\dfrac{-17}{8}\)

\(=\dfrac{17}{12}.\dfrac{-8}{17}\)

\(=\dfrac{-2}{3}\)

dễ

(7-5/24+0,75+7/12):(-2 1/8)

17/12:-17/8=-2/3

k minh nhe

\(\left(\dfrac{-5}{24}+0,75+\dfrac{7}{12}\right):\left(-2\dfrac{1}{8}\right)\)

có ai ko giúp với