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17 tháng 9 2018

\(2\frac{1}{2}\cdot2\frac{3}{4}=\frac{5}{2}\cdot\frac{11}{4}=\frac{55}{8}\)

17 tháng 9 2018

2 1/2 x 2 3/4 = 2 x 2 + 1 / 2 x 2 x 4 + 3 / 4 = 5/2 x 11/4 = 55/8

3 tháng 8 2023

a) \(...=\dfrac{19}{8}:\dfrac{15}{4}x\dfrac{8}{3}=\dfrac{19}{8}x\dfrac{4}{15}x\dfrac{8}{3}=\dfrac{76}{45}\)

b) \(...=\dfrac{3}{2}:\dfrac{7}{3}:\dfrac{17}{6}=\dfrac{3}{2}x\dfrac{3}{7}x\dfrac{6}{17}=\dfrac{27}{119}\)

c) \(...=\dfrac{14}{3}-\dfrac{7}{4}:\dfrac{12}{5}=\dfrac{14}{3}-\dfrac{7}{4}x\dfrac{5}{12}=\dfrac{14}{3}-\dfrac{35}{48}=\dfrac{14x16}{48}-\dfrac{35}{48}=\dfrac{224}{48}-\dfrac{35}{48}=\dfrac{189}{48}=\dfrac{63}{16}\)

3 tháng 8 2023

\(a,2\dfrac{3}{8}:3\dfrac{3}{4}\times2\dfrac{2}{3}\\ =\dfrac{2\times8+3}{8}:\dfrac{3\times4+3}{4}\times\dfrac{2\times3+2}{3}\\ =\dfrac{19}{8}:\dfrac{15}{4}\times\dfrac{8}{3}\\ =\dfrac{19\times4\times8}{8\times15\times3}=\dfrac{76}{45}\)

\(b,1\dfrac{1}{2}:\dfrac{7}{3}:2\dfrac{5}{6}\\ =\dfrac{3}{2}:\dfrac{7}{3}:\dfrac{2\times6+5}{6}\\ =\dfrac{3}{2}\times\dfrac{3}{7}\times\dfrac{6}{17}\\ =\dfrac{54}{238}=\dfrac{27}{119}\)

\(c,4\dfrac{2}{3}-1\dfrac{3}{4}:2\dfrac{2}{5}\\ =\dfrac{4\times3+2}{3}-\dfrac{1\times4+3}{4}:\dfrac{2\times5+2}{5}\\ =\dfrac{14}{3}-\dfrac{7}{4}:\dfrac{12}{5}\\ =\dfrac{14}{3}-\dfrac{7}{4}.\dfrac{5}{12}\\ =\dfrac{14}{3}-\dfrac{35}{48}\\ =\dfrac{14\times16-35}{48}=\dfrac{189}{48}=\dfrac{63}{16}\)

31 tháng 7 2023

\(4\dfrac{2}{3}+3\dfrac{2}{7}=\dfrac{14}{3}+\dfrac{23}{7}=\dfrac{14x7+23x3}{21}=\dfrac{167}{21}\)

\(8\dfrac{5}{9}:5\dfrac{1}{2}=\dfrac{77}{9}:\dfrac{11}{2}=\dfrac{77}{9}x\dfrac{2}{11}=\dfrac{14}{9}\)

\(6\dfrac{5}{7}:2\dfrac{1}{6}=\dfrac{47}{7}:\dfrac{13}{6}=\dfrac{47}{7}x\dfrac{6}{13}=\dfrac{282}{91}\)

\(1\dfrac{3}{4}x2\dfrac{5}{6}=\dfrac{7}{4}x\dfrac{17}{6}=\dfrac{119}{24}\)

\(5\dfrac{3}{4}-2=\dfrac{23}{4}-2=\dfrac{23}{4}-\dfrac{8}{4}=\dfrac{15}{4}\)

10 tháng 9 2021

\(2\dfrac{1}{3}.\left(x+\dfrac{1}{2}\right)x=3\dfrac{3}{4}\)

<=> \(\dfrac{7}{3}x\left(x+\dfrac{1}{2}\right)=\dfrac{15}{4}\)

<=> \(\dfrac{7}{3}x^2+\dfrac{7}{6}=\dfrac{15}{4}\)

<=> \(\dfrac{7}{3}x^2=\dfrac{15}{4}-\dfrac{7}{6}\)

<=> \(\dfrac{7}{3}x^2=\dfrac{31}{12}\)

<=> x2 = \(\dfrac{31}{12}:\dfrac{7}{3}\)

<=> x2 = \(\dfrac{31}{28}\)

<=> x = \(\dfrac{\sqrt{217}}{14}\)

10 tháng 9 2021

√217/14 là bao nhiêu vậy

17 tháng 7 2019

\(x\)là dấu nhân ak ???..........

\(\left(y-\frac{3}{4}\right).2+\frac{1}{2}-\frac{3}{2}=1\)

\(\Leftrightarrow2y-\frac{3}{2}+\frac{1}{2}-\frac{3}{2}=1\)

\(\Leftrightarrow2y-\frac{5}{2}=1\)

\(\Leftrightarrow2y=1+\frac{5}{2}\)

\(\Leftrightarrow2y=\frac{7}{2}\)

\(\Leftrightarrow y=\frac{7}{4}\)

26 tháng 9 2015

1/1 x2 + 1/ 2 x 3 + 1/ 3 x 4 + ................. + 1/ 2013 x 2014

= 1/1 – 1/2 + 1/2 – 1/3 + 1/3 – 1/4 + ........................ + 1/2013 – 1/2014

= 1 – 1/2014 = 2013/2014

12 tháng 8 2023

a)\(a+a+a+\dfrac{1}{2}x2\dfrac{2}{5}+a+\dfrac{14}{5}+a=134\)

\(5xa+\dfrac{1}{2}x\dfrac{12}{5}+\dfrac{14}{5}=134\)

\(5xa+\dfrac{12}{10}+\dfrac{14}{5}=134\)

\(5xa+\dfrac{6}{5}+\dfrac{14}{5}=134\)

\(5xa+4=134\)

\(5xa=134-4=130\)

\(a=130:5=26\)

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

\(\dfrac{54}{10}-yx\dfrac{3}{4}=\dfrac{2}{3}\)

\(yx\dfrac{3}{4}=\dfrac{54}{10}-\dfrac{2}{3}\)

\(yx\dfrac{3}{4}=\dfrac{71}{15}\)

\(y=\dfrac{71}{15}:\dfrac{3}{4}\)

\(y=\dfrac{284}{45}\)

19 tháng 6 2020

Bài 1: Tính

a)  =1\(\frac{49}{60}\)

b)  =2\(\frac{13}{30}\)

Bài 2: Tìm x

a)  =4\(\frac{1}{21}\)

Riêng câu b) thì mk nghĩ là bạn viết lộn vì mk thấy cái chỗ xx3/4 là mk ko hiểu rồi

21 tháng 3 2023

a,

�+�×14÷27+�÷29=255

⇒�+�×14×72+�×92=255

⇒�+�×78+�×92=255

⇒�.(1+78+92)=255

⇒�⋅518=255

⇒�=255÷518

⇒�=255×851

⇒�=40

Vậy x = 40 

 

20 tháng 3 2023

A=\(\dfrac{18360}{151}\)

B=\(\dfrac{1510}{3}\)