K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

7 tháng 4 2022

4/15 : y = (8/10 +5/10) x 4/13

4/15: y = 13/10 x 4/13

4/15 : y = 4/10 = 2/5

y= 4/15 : 2/5

y= 4/15 x 5/2

y =20/30 =2/3

4/15 : y = ( 4/5 + 1/2 ) x 4/13

4/5 : y = 13/10 x 4/13

4/15 : y = 2/5

y = 4/15 : 2/5 

y = 2/3

14 tháng 4 2019

\(\frac{4}{15}:y=\left(\frac{4}{5}+\frac{1}{2}\right)\times\frac{4}{13}\)

\(\frac{4}{15}:y=\frac{13}{10}\times\frac{4}{13}\)

\(\frac{4}{15}:y=\frac{2}{5}\)

\(y=\frac{4}{15}:\frac{2}{5}\)

\(y=\frac{2}{3}\)

14 tháng 4 2019

\(\frac{4}{15}:y=\left(\frac{4}{5}+\frac{1}{2}\right)\times\frac{4}{13}\)

\(\frac{4}{15}:y=\frac{13}{10}\times\frac{4}{13}\)

\(\frac{4}{15}:y=\frac{2}{5}\)

\(y=\frac{4}{15}:\frac{2}{5}\)

\(y=\frac{2}{3}\)

14 tháng 4 2019

\(\frac{4}{15}:y=\left(\frac{8}{10}+\frac{5}{10}\right)X\frac{4}{13}\)

\(\frac{4}{15}:y=\frac{13}{10}X\frac{4}{13}\)

\(\frac{4}{15}:y=\frac{2}{5}\)

\(y=\frac{4}{15}:\frac{2}{5}\)

\(y=\frac{4}{15}X\frac{5}{2}\)

\(y=\frac{2}{3}\)

HOK TỐT

1) Ta có: \(\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{7}{25}\cdot\dfrac{5}{7}\right)\)

\(=\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{1}{5}\right)\)

=0

2) Ta có: \(\dfrac{8}{17}\cdot\dfrac{4}{15}+\dfrac{8}{17}\cdot\dfrac{22}{15}-\dfrac{8}{15}\cdot\dfrac{9}{17}\)

\(=\dfrac{8}{17}\left(\dfrac{4}{15}+\dfrac{22}{15}-\dfrac{9}{15}\right)\)

\(=\dfrac{8}{17}\cdot\dfrac{15}{15}=\dfrac{8}{17}\)

3) Ta có: \(\dfrac{2021}{2}\cdot\dfrac{1}{3}+\dfrac{4042}{4}\cdot\dfrac{1}{5}+\dfrac{6063}{3}\cdot\dfrac{22}{15}\)

\(=\dfrac{2021}{2}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)+2021\cdot\dfrac{22}{15}\)

\(=\dfrac{2021}{2}\cdot\dfrac{8}{15}+\dfrac{2021}{2}\cdot\dfrac{44}{15}\)

\(=\dfrac{2021}{2}\cdot\dfrac{52}{15}\)

\(=\dfrac{52546}{15}\)

4) Ta có: \(\dfrac{4}{7}\cdot\dfrac{2}{13}+\dfrac{8}{13}:\dfrac{7}{4}+\dfrac{4}{7}:\dfrac{13}{2}+\dfrac{4}{7}\cdot\dfrac{1}{13}\)

\(=\dfrac{4}{7}\left(\dfrac{2}{13}+\dfrac{8}{13}+\dfrac{2}{13}+\dfrac{1}{13}\right)\)

\(=\dfrac{4}{7}\)

2 tháng 7 2021

cảm ơn nhé

vui

1 tháng 5 2019

Chứng minh P>3 nha!!! 

1 tháng 5 2019

Chứng minh P>3 nha!!! 

28 tháng 9 2021

h) \(\left\{{}\begin{matrix}\dfrac{1}{x}+\dfrac{1}{y}=2\\\dfrac{3}{x}-\dfrac{4}{y}=-1\end{matrix}\right.\)\(\left(1\right)\)\(\left(đk:x,y\ne0\right)\)

Đặt \(a=\dfrac{1}{x},b=\dfrac{1}{y}\)

\(\left(1\right)\Leftrightarrow\) \(\left\{{}\begin{matrix}a+b=2\\3a-4b=-1\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}3a+3b=6\\3a-4b=-1\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}a+b=2\\7b=7\end{matrix}\right.\)\(\Leftrightarrow a=b=1\)

Thay a,b:

\(\Leftrightarrow\dfrac{1}{x}=\dfrac{1}{y}=1\Leftrightarrow x=y=1\left(tm\right)\)

7 tháng 8 2019

\(1,\frac{2}{3}+\frac{4}{9}+\frac{1}{5}+\frac{2}{15}+\frac{3}{2}-\frac{17}{18}\)

\(< =>\frac{4}{9}+\frac{3}{2}+\left(\frac{2}{3}+\frac{1}{5}+\frac{2}{15}\right)-\frac{17}{18}\)

\(< =>\frac{8}{18}+\frac{27}{18}+\left(\frac{10}{15}+\frac{3}{15}+\frac{2}{15}\right)-\frac{17}{18}\)

\(< =>\frac{35}{18}+1-\frac{17}{18}\)

\(< =>\frac{53}{18}-\frac{17}{18}\)

\(< =>2\)

\(2,\frac{13}{28}\cdot\frac{5}{12}-\frac{5}{28}\cdot\frac{1}{12}\)

\(< =>\left(\frac{13}{28}-\frac{5}{28}\right)\cdot\left(\frac{5}{12}-\frac{1}{12}\right)\)

\(< =>\frac{2}{7}\cdot\frac{1}{3}\)

\(< =>\frac{2}{21}\)

\(3,\frac{19}{4}\cdot\frac{15}{23}-\frac{15}{4}\cdot\frac{7}{23}+\frac{15}{4}\cdot\frac{11}{23}\)

\(< =>\frac{285}{92}-\frac{105}{92}+\frac{165}{92}\)

\(< =>\frac{15}{4}\)

8 tháng 8 2019

cảm ơn bạn nha bạn chắc chăn đúng không

5 tháng 3 2022

a,\(\frac{1}{5}\times\frac{2}{9}\div\frac{1}{15}\)

\(=\frac{1}{5}\times\frac{2}{9}\times15\)

\(=\left(\frac{1}{5}\times15\right)\times\frac{2}{9}\)

\(=3\times\frac{2}{9}\)

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

b\(\frac{4}{15}\times\frac{7}{15}\times\frac{5}{4}\)

\(=\left(\frac{4}{15}\times\frac{5}{4}\right)\times\frac{7}{15}\)

\(=\frac{1}{3}\times\frac{7}{15}\)

\(=\frac{7}{45}\)

c,\(\frac{21}{23}\times\frac{5}{11}\times\frac{44}{?}\)

d,\(26\times\frac{13}{42}\div13\)

\(=\left(26\div13\right)\times\frac{13}{42}\)

\(=2\times\frac{13}{42}\)

\(=\frac{13}{21}\)

5 tháng 3 2022

ờ ờ .......................... hong bt

1: x=3/4-1/2=3/4-2/4=1/4

2: x-1/5=2/11

=>x=2/11+1/5=21/55

3: x-5/6=16/42-8/56

=>x-5/6=8/21-4/28=5/21

=>x=5/21+5/6=15/14

4: x/5=5/6-19/30

=>x/5=25/30-19/30=6/30=1/5

=>x=1

5: =>|x|=1/3+1/4=7/12

=>x=7/12 hoặc x=-7/12

6: x=-1/2+3/4

=>x=3/4-1/2=1/4

11: x-(-6/12)=9/48

=>x+1/2=3/16

=>x=3/16-1/2=-5/16

21 tháng 7 2023

1)x= 1/4

2)x= 2/11+ 1/5

   x= 21/55

3)x - 5/6 = 5/21

   x         = 5/21+5/6

   x         = 15/14

4)x/5 = 5/6 + -19/30

   x:5 = 1/5

   x    = 1/5.5

   x    = 1

5) |x| - 1/4 = 6/18

    |x|           = 6/18 - 1/4

    |x|            =7/12

⇒x= 7/12 hoặc -7/12

6)x = -1/2 +3/4

   x= 1/4

7) x/15 = 3/5 + -2/3

   x:15  = -1/15

  x        = -1/15. 15

  x        = -1

8)11/8 + 13/6 = 85/x  

       85/24      = 85/x

  ⇒      x           = 24

9) x - 7/8 = 13/12

   x          = 13/12 + 7/8

   x          = 47/24

10)x - -6/15 = 4/27  

     x            = 4/27 + (-6/15)

    x             = -34/135

11) -(-6/12)+x = 9/48

                    x= 9/48 - 6/12

                    x = -5/16

12) x - 4/6 = 5/25 + -7/15

      x -4/6  =  -4/15

     x           = -4/15 + 4/6

    x             = 2/5

2 tháng 8 2016

13/15-(y.4/15-2/9).3/5=1/5

(y.4/15-2/9).3/5=13/15-1/5

(y.4/15-2/9).3/5=2/3

y.4/15-2/9=2/3:3/5

y.4/15-2/9=10/9

y.4/15=10/9+2/9

y.4/15=4/3

y=4/3:4/15

y=5

Những chỗ có dấu "." thì thay bằng dấu nhân