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2 tháng 4 2019

1)

a)

\(\frac{-5}{6}.\frac{120}{25}< x< \frac{-7}{15}.\frac{9}{14}\)

\(\frac{-1}{1}.\frac{20}{5}< x< \frac{-1}{5}.\frac{3}{2}\)

\(\frac{-20}{5}< x< \frac{-3}{10}\)

\(\frac{-40}{10}< x< \frac{-3}{10}\)

\(\Rightarrow Z\in\left\{-4;-5;-6;-7;-8;-9;-10;...;-39\right\}\)

2 tháng 4 2019

\(\left(\frac{-5}{3}\right)^3< x< \frac{-24}{35}.\frac{-5}{6}\)

\(\frac{25}{3}< x< \frac{-4}{7}.\frac{1}{1}\)

\(\frac{-25}{3}< x< \frac{-4}{7}\)

\(\frac{-175}{21}< x< \frac{-12}{21}\)

\(\Rightarrow Z\in\left\{-13;-14;-15;-16;...;-174\right\}\)

23 tháng 4 2019

\(\frac{2}{7}.\left(5\frac{1}{4}-3\frac{1}{4}\right)\)

\(\frac{2}{7}.2\)

\(\frac{4}{7}\)

23 tháng 4 2019

    \(\frac{2}{7}.5\frac{1}{4}-\frac{2}{7}.3\frac{1}{4}\)

=> \(\frac{2}{7}.\left(5\frac{1}{4}-3\frac{1}{4}\right)\)

=> \(\frac{2}{7}.2\)

=> \(\frac{4}{7}\)

#Hk_tốt

#Ngọc's_Ken'z

6 tháng 6 2020

a, \(\frac{2}{5}.\frac{1}{3}-\frac{2}{15}:\frac{1}{5}+\frac{3}{5}.\frac{1}{3}\)

\(=\frac{1}{3}.\left(\frac{2}{5}+\frac{3}{5}\right)-\frac{2}{15}.5\)

\(=\frac{1}{3}.1-\frac{2}{3}\)

\(=\frac{1}{3}-\frac{2}{3}\)

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

b, \(\left(6-2\frac{4}{5}\right).3\frac{1}{8}+1\frac{3}{8}:\frac{1}{4}\)

\(=\left(6-\frac{14}{5}\right).\frac{25}{8}+\frac{11}{8}.4\)

\(=\frac{16}{5}.\frac{25}{8}+\frac{11}{2}\)

\(=10+\frac{11}{2}\)

\(=\frac{31}{2}\)

1/3×(3/5+2/5)-2/15×1/5

1/3×1-2/15×1/5

1/3-2/15×1/5

1/3-2/75

25/75-2/75

23/75

(6-14/5)×25/8-11/8:4/1

16/5×25/8-11/8:4/1

10/1-11/8:4/1

10/1-11/8×1/4

10/1-11/32

320/32-11/32

309/32

\(\left(\frac{-3}{42}+\frac{10}{-21}-\frac{-9}{14}\right).\left(\frac{-7}{5}\right).\)

\(=\left(\frac{-1}{14}-\frac{10}{21}+\frac{9}{14}\right).\left(\frac{-7}{5}\right)\)

\(\left(\frac{12}{21}-\frac{10}{21}\right).\left(\frac{-7}{5}\right)=\frac{2.\left(-7\right)}{21.5}=\frac{-2}{15}\)

2 tháng 4 2017

khó quá 

2 tháng 4 2017

\(a.\frac{-5}{9}+\frac{5}{9}:A=\left(-\frac{5}{9}+\frac{5}{9}\right):A=0:A=0\)

\(b.\frac{7}{25}.\frac{11}{13}-\frac{7}{25}.\frac{2}{13}-\frac{8}{25}=\frac{7}{25}.\left(\frac{11}{13}-\frac{2}{13}\right)-\frac{8}{25}=\frac{7}{25}.\frac{9}{13}-\frac{8}{25}=\frac{63}{325}-\frac{8}{25}=\frac{-41}{325}\)

C.Thua

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25 tháng 4 2018

= [ 60/90 - ( 12/15 + 10/15) ] : 6/5

= ( 2/3 - 22/15 ) x 5/6

= ( 10/15 - 22/15 ) x 5/6

= -12/15 x 5/6

= -60/90

= -2/3

25 tháng 4 2018

( 15/10 x 4/9 - ( 4/5 + 2/3 )) : 6/5

( 15/10 x 4/9 - ( 12/15 + 10/15 )) : 6/5

(30/45 - 66/45 ) : 6/5

-12/15 : 6/5 ( đã rút gọn -36/45 = -12/15 )

-2/3

k mk na <3