tìm các số nguyên x, y biết a, \(\dfrac{24}{7x-3}\)=\(\dfrac{-4}{25}\) b, \(\dfrac{4}{x-6}\)=\(\dfrac{y}{24}\)=\(\dfrac{-12}{18}\) c, \(\dfrac{-1}{5}\)

1

DT

dương trà my

11 tháng 7 2017

giúp zới

Tìm các số nguyên x,y biết:a)\(\dfrac{6}{2x+1}=\dfrac{2}{7}\)b) \(\dfrac{24}{7x-3}=\dfrac{-4}{25}\)c) \(\dfrac{4}{x-6}=\dfrac{y}{24}=\dfrac{-12}{18}\)d) \(\dfrac{-1}{5}\le\dfrac{x}{8}\le\dfrac{1}{4}\)e) \(\dfrac{x+46}{20}=x\dfrac{2}{5}\)f) \(y\dfrac{5}{y}=\dfrac{86}{y}\) ( \(x\dfrac{2}{5};y\dfrac{5}{y}\) là các hỗn...

TT

Trần Tiến Đạt

8 tháng 6 2021

1

OY

OH-YEAH^^

8 tháng 6 2021

a,\(\dfrac{6}{2x+1}=\dfrac{2}{7}\)

⇒\(\dfrac{6}{2x+1}=\dfrac{6}{21}\)

⇒\(2x+1=21\)

\(2x=21-1\)

\(2x=20\)

⇒\(x=10\)

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L3

Lily :33

30 tháng 6 2021

Tìm số nguyên x, y biết:

a, \(\dfrac{-1}{5}\)≤ \(\dfrac{x}{8}\)≤ \(\dfrac{1}{4}\)

b, \(\dfrac{4}{x-6}\)= \(\dfrac{y}{24}\)= \(\dfrac{-12}{18}\)

c, \(\dfrac{x+46}{20}\)=x \(\dfrac{2}{5}\)

1

T

꧁_͏ͥ͏_͏ͣ͏_͏ͫ͏ ¡亗ᵛᶰシ๖ۣۜT๖ۣۜR๖ۣۜÂ๖ۣ...

30 tháng 6 2021

Giải:

a) \(\dfrac{-1}{5}\le\dfrac{x}{8}\le\dfrac{1}{4}\)

\(\Rightarrow\dfrac{-8}{40}\le\dfrac{5x}{40}\le\dfrac{10}{40}\)

\(\Rightarrow5x\in\left\{0;\pm5;10\right\}\)

\(\Rightarrow x\in\left\{0;\pm1;2\right\}\)

b) \(\dfrac{4}{x-6}=\dfrac{y}{24}=\dfrac{-12}{18}\)

\(\Rightarrow\dfrac{4}{x-6}=\dfrac{-12}{18}\)

\(\Rightarrow-12.\left(x-6\right)=4.18\)

\(\Rightarrow-12x+72=72\)

\(\Rightarrow-12x=72-72\)

\(\Rightarrow-12x=0\)

\(\Rightarrow x=0:-12\)

\(\Rightarrow x=0\)

\(\Rightarrow\dfrac{y}{24}=\dfrac{-12}{18}\)

\(\Rightarrow y=\dfrac{-12.24}{18}=-16\)

c) \(\dfrac{x+46}{20}=x.\dfrac{2}{5}\)

\(\dfrac{x+46}{20}=\dfrac{2x}{5}\)

\(\Rightarrow5.\left(x+46\right)=2x.20\)

\(\Rightarrow5x+230=40x\)

\(\Rightarrow5x-40x=-230\)

\(\Rightarrow-35x=-230\)

\(\Rightarrow x=-230:-35\)

\(\Rightarrow x=\dfrac{46}{7}\)

Chúc bạn học tốt!

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DT

dang tran thai binh

13 tháng 8 2017

tìm các số nguyên x,y:

a, \(\dfrac{6}{2x+1}=\dfrac{2}{7}\)

b,\(\dfrac{24}{7x-3}=\dfrac{-4}{25}\)

c,\(\dfrac{4}{x-6}=\dfrac{y}{24}=\dfrac{-12}{18}\)

d,\(\dfrac{-1}{5}< \dfrac{x}{8}< \dfrac{1}{4}\)

#Toán lớp 7

1

NT

Nguyễn Thị Thu

13 tháng 8 2017

a. \(\dfrac{6}{2x+1}=\dfrac{2}{7}\Rightarrow\dfrac{6}{2x+1}=\dfrac{6}{21}\Rightarrow2x+1=21\)

\(\Rightarrow2x=21-1=20\Rightarrow x=\dfrac{20}{2}=10\)

Vậy x = 10

b. \(\dfrac{24}{7x-3}=\dfrac{-4}{25}\Rightarrow\dfrac{24}{7x-3}=\dfrac{24}{150}\Rightarrow7x-3=150\)

\(\Rightarrow7x=150+3=153\Rightarrow x=\dfrac{153}{7}\)

Vậy \(x=\dfrac{153}{7}\)

c. \(\dfrac{4}{x-6}=\dfrac{-12}{18}\Rightarrow-12\cdot\left(x-6\right)=4\cdot18=72\)

\(\Rightarrow x-6=\dfrac{72}{-12}=-6\Rightarrow x=-6+6=0\)

\(\dfrac{y}{24}=\dfrac{-12}{18}\Rightarrow y=\dfrac{-12\cdot24}{18}=-16\)

Vậy x = 0 ; y = -16

tìm các số nguyên x,y biết \(\dfrac{6}{2x+1}=\dfrac{2}{7}\) \(\dfrac{24}{7x-3}=\dfrac{-4}{25}\) \(\dfrac{4}{x-6}=\dfrac{y}{24}=\dfrac{-12}{18}\) \(\dfrac{-1}{5}\le\dfrac{x}{8}\le\dfrac{1}{4}\) \(\dfrac{x+46}{20}=x\dfrac{2}{5}\) \(y\dfrac{5}{y}=\dfrac{56}{y}\) \(\left(x\dfrac{2}{5};y\dfrac{5}{y}\right)\) là các hỗn số...

NH

Nguyễn Huế

9 tháng 6 2017

#Toán lớp 7

5

NC

NGUYỄN CẨM TÚ

9 tháng 6 2017

\(\dfrac{6}{2x+1}=\dfrac{2}{7}\)

=> 2(2x+1) = 6.7

4x+2=42

4x=40

x=10

Vậy x=10

NT

Nguyễn Trần Thành Đạt

9 tháng 6 2017

a)\(\dfrac{6}{2x+1}=\dfrac{2}{7}\\ =>6.7=2.\left(2x+1\right)\\ =>2x+1=\dfrac{6.7}{2}=\dfrac{42}{2}=21\\ =>2x=21-1=20\\ =>x=\dfrac{20}{2}=10\)

b) \(\dfrac{24}{7x-3}=-\dfrac{4}{25}\\ =>24.25=-4.\left(7x-3\right)\\ =>7x-3=\dfrac{24.25}{-4}=-150\\ =>7x=-150+3=-147\\ =>x=\dfrac{-147}{7}=-21\)

c) \(\dfrac{4}{x-6}=\dfrac{y}{24}=-\dfrac{12}{18}\\ =>x-6=\dfrac{4.18}{-12}=-6\\ =>x=-6+6=0\\ y=\dfrac{-12.24}{18}=-16\)

d) \(-\dfrac{1}{5}\le\dfrac{x}{8}\le\dfrac{1}{4}\\ < =>-\dfrac{8}{40}\le-\dfrac{5x}{40}\le\dfrac{10}{40}\\ =>-8\le-5x\le10\\ Mà:-8< -5.1< -5.0< -5.\left(-1\right)< -5.\left(-2\right)=10\\ =>x\in\left\{-2;-1;0;1\right\}\)

e) \(\dfrac{x+46}{20}=x\dfrac{2}{5}\\ < =>\dfrac{x+46}{20}=\dfrac{5x+2}{5}\\ =>5\left(x+46\right)=20\left(5x+2\right)\\ < =>5x+230=100x+40\\ < =>230-40=100x-5x\\ < =>190=95x\\ =>x=\dfrac{190}{95}=2\)

f) \(y\dfrac{5}{y}=\dfrac{56}{y}\\ < =>\dfrac{y^2+5}{y}=\dfrac{56}{y}\\ =>y\left(y^2+5\right)=56y\\ =>y^2+5=\dfrac{56y}{y}=56\\ =>y^2=56-5=51\\ =>y=\sqrt{51}\)

KJ

❖ Khang/GD❄ 『ʈєɑɱ❖Hoàng๖ۣۜGia☆』

28 tháng 12 2021

Tìm số nguyên x, y biết:

\(a,\dfrac{x}{5}=\dfrac{-18}{10}\) b, \(\dfrac{6}{x-1}=\)\(\dfrac{-3}{7}\) c, \(\dfrac{y-3}{12}\)=\(\dfrac{3}{y-3}\) d, \(\dfrac{x}{25}\)=\(\dfrac{-5}{x^2}\)

1

I

ILoveMath

28 tháng 12 2021

\(a,\dfrac{x}{5}=\dfrac{-18}{10}\\ \Rightarrow x=-\dfrac{18}{10}.5\\ \Rightarrow x=-9\\ b,\dfrac{6}{x-1}=\dfrac{-3}{7}\\ \Rightarrow6.7=-3\left(x-1\right)\\ \Rightarrow42=-3x+3\\ \Rightarrow42+3x-3=0\\ \Rightarrow3x+39=0\\ \Rightarrow3x=-39\\ \Rightarrow x=-13\\ c,\dfrac{y-3}{12}=\dfrac{3}{y-3}\\ \Rightarrow\left(y-3\right)^2=36\\ \Rightarrow\left[{}\begin{matrix}y-2=6\\y-2=-6\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}y=8\\y=-4\end{matrix}\right.\)

\(d,\dfrac{x}{25}=\dfrac{-5}{x^2}\\ \Rightarrow x^3=-125\\ \Rightarrow x^3=\left(-5\right)^3\\ \Rightarrow x=-5\)

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LN

Lương Nữ Thiên Trúc

19 tháng 7 2018

Tìm x,y biết

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

b) \(\left(\dfrac{-5}{3}\right)^2< x< \dfrac{-24}{35}.\dfrac{-5}{6}\)

c) \(\dfrac{1}{18}< \dfrac{x}{12}< \dfrac{y}{9}< \dfrac{1}{4}\)

d) \(\dfrac{x-4}{y-3}=\dfrac{4}{3}\) và x-y = 5

Nhanh nha đến ngày 20/7

1

NT

Nguyen Thi Huyen

19 tháng 7 2018

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

\(\Rightarrow-4< x< \dfrac{-3}{10}\)

\(\Rightarrow\dfrac{-40}{10}< x< \dfrac{-3}{10}\)

\(\Rightarrow x\in\left\{\dfrac{-39}{10};\dfrac{-38}{10};\dfrac{-37}{10};...;\dfrac{-5}{10};\dfrac{-4}{10}\right\}\)

b) \(\left(\dfrac{-5}{3}\right)^2< x< \dfrac{-24}{35}.\dfrac{-5}{6}\)

\(\Rightarrow\dfrac{25}{9}< x< \dfrac{4}{7}\)

\(\Rightarrow\dfrac{175}{63}< x< \dfrac{36}{63}\)

\(\Rightarrow x=\varnothing\)

c) \(\dfrac{1}{18}< \dfrac{x}{12}< \dfrac{y}{9}< \dfrac{1}{4}\)

\(\Leftrightarrow\dfrac{2}{36}< \dfrac{3x}{36}< \dfrac{4y}{36}< \dfrac{9}{36}\)

\(\Rightarrow x\in\left\{1;2\right\}\)

+) Với \(x=1\)

\(\Rightarrow y\in\left\{1;2\right\}\)

+) Với \(x=2\)

\(\Rightarrow y=2\)

Vậy \(x=1\) thì \(y\in\left\{1;2\right\}\); \(x=2\) thì \(y=8\).

Tìm số nguyên x , y biết :a) \(\dfrac{x}{15}=\dfrac{17}{51}\) b) \(\dfrac{-7}{y}=\dfrac{12}{24}\)C2. Tìm tập hợp các phân số bằng phân số :a) \(\dfrac{5}{12}\) b) \(\dfrac{2323}{2424}\)C3. Một lớp có 43 HS nữ . Hỏi số nữ bằng mấy phần số nam .C4. Rút gọn các phân số sau :a) \(\dfrac{2.7.13}{26.35}\) b) \(\dfrac{23.5-23}{4-27}\) ...

MT

Miru Tōmorokoshi

1 tháng 8 2021

Tìm x biết: a) \(\dfrac{6}{-x}=\dfrac{x}{-24}\) b) \(x-\dfrac{7}{12}x+\dfrac{3}{8}x=\dfrac{5}{24}\) c)\(\left(x-\dfrac{1}{3}\right)^2-\dfrac{1}{2}=1\dfrac{3}{4}\) d) \(\dfrac{x-3}{-2}=\dfrac{-8}{x-3}\) e) \(\dfrac{9}{x}=\dfrac{-35}{105}\) ...

2

OY

OH-YEAH^^

1 tháng 8 2021

Bài 4:

a) \(\dfrac{2.7.13}{26.35}=\dfrac{2.7.13}{13.2.7.5}=\dfrac{1}{5}\)

b) \(\dfrac{23.5-23}{4-27}=\dfrac{23.\left(5-1\right)}{-23}=\dfrac{23.4}{-23}=-4\)

c) \(\dfrac{2130-15}{3550-25}=\dfrac{2115}{3525}=\dfrac{3}{5}\)

Đúng(2)

OY

OH-YEAH^^

1 tháng 8 2021

Bài 1

a) \(\dfrac{x}{15}=\dfrac{17}{51}\)

51x=17.15

51x=255

⇒x=5

b) \(\dfrac{-7}{y}=\dfrac{12}{24}\)

-7.24=24y

-168=12y

⇒y=-14

Đúng(1)

TT

Trần Thị Thảo

18 tháng 4 2022

1

NL

Nguyễn Lê Phước Thịnh

29 tháng 6 2023

a: =>6/x=x/24

=>x^2=144

=>x=12 hoặc x=-12

b: =>x(1-7/12+3/8)=5/24

=>x*19/24=5/24

=>x=5/24:19/24=5/19

c: =>(x-1/3)^2=1+3/4+1/2=9/4

=>x-1/3=3/2 hoặc x-1/3=-3/2

=>x=11/6 hoặc x=-7/6

d: =>(x-3)^2=16

=>x-3=4 hoặc x-3=-4

=>x=-1 hoặc x=7

e: =>9/x=-1/3

=>x=-27

f: =>x-1/2=0 hoặc -x/2-3=0

=>x=1/2 hoặc x=-6

Tìm x, y, z, t ∈ Z biết:a, \(\dfrac{5}{x}=\dfrac{-10}{12}\) b, \(\dfrac{4}{-6}=\dfrac{x+3}{9}\) c, \(\dfrac{x-1}{25}=\dfrac{4}{x-1}\) ...

KJ

❖ Khang/GD❄ 『ʈєɑɱ❖Hoàng๖ۣۜGia☆』

4 tháng 1 2022