Tìm x: a/$\dfrac{x-1}{x+5}=\dfrac{6}{7}$ b/$\dfrac{x^2}{-6}=-\dfrac{24}{25}$ c/$\dfrac{x+4}{20}=\dfrac{5}{x+4}$...

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Dương Thanh Ngân

13 tháng 7 2018

Tìm x:

a/$\dfrac{x-1}{x+5}=\dfrac{6}{7}$

b/$\dfrac{x^2}{-6}=-\dfrac{24}{25}$

c/$\dfrac{x+4}{20}=\dfrac{5}{x+4}$

d/$2,5:4x=0,5:0,2$

e/$\dfrac{1}{5}x:3=\dfrac{2}{3}:0,25$

g/$1,25:0,8=\dfrac{3}{8}:0,2x$

f/$-3:\left(-2\dfrac{1}{4}\right)=\dfrac{3}{4}:\left(-6x\right)$

h/$3:\dfrac{2}{5}x=1:0,01$

j/$2:1\dfrac{1}{4}=\dfrac{1}{2}:2x$

l/$\dfrac{4}{x-1}=\dfrac{x-1}{9}$

#Toán lớp 7

Ngô Thị Thu Trang

15 tháng 7 2018

Thu thập số liệu, tần số

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Ngô Thị Thu Trang

13 tháng 7 2018

Thu thập số liệu, tần số

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Các câu hỏi dưới đây có thể giống với câu hỏi trên

Nguyễn Thu Huyền

1 tháng 9 2023

Tìm...

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#Toán lớp 7

Toru

1 tháng 9 2023

$a,3-x=x+1,8$

$\Rightarrow-x-x=1,8-3$

$\Rightarrow-2x=-1,2$

$\Rightarrow x=0,6$

$b,2x-5=7x+35$

$\Rightarrow2x-7x=35+5$

$\Rightarrow-5x=40$

$\Rightarrow x=-8$

$c,2\left(x+10\right)=3\left(x-6\right)$

$\Rightarrow2x+20=3x-18$

$\Rightarrow2x-3x=-18-20$

$\Rightarrow-x=-38$

$\Rightarrow x=38$

$d,8\left(x-\dfrac{3}{8}\right)+1=6\left(\dfrac{1}{6}+x\right)+x$

$\Rightarrow8x-3+1=1+6x+x$

$\Rightarrow8x-3=7x$

$\Rightarrow8x-7x=3$

$\Rightarrow x=3$

$e,\dfrac{2}{9}-3x=\dfrac{4}{3}-x$

$\Rightarrow-3x+x=\dfrac{4}{3}-\dfrac{2}{9}$

$\Rightarrow-2x=\dfrac{10}{9}$

$\Rightarrow x=-\dfrac{5}{9}$

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Toru

1 tháng 9 2023

$g,\dfrac{1}{2}x+\dfrac{5}{6}=\dfrac{3}{4}x-\dfrac{1}{2}$

$\Rightarrow\dfrac{1}{2}x-\dfrac{3}{4}x=-\dfrac{1}{2}-\dfrac{5}{6}$

$\Rightarrow-\dfrac{1}{4}x=-\dfrac{4}{3}$

$\Rightarrow x=\dfrac{16}{3}$

$h,x-4=\dfrac{5}{6}\left(6-\dfrac{6}{5}x\right)$

$\Rightarrow x-4=5-x$

$\Rightarrow x+x=5+4$

$\Rightarrow2x=9$

$\Rightarrow x=\dfrac{9}{2}$

$k,7x^2-11=6x^2-2$

$\Rightarrow7x^2-6x^2=-2+11$

$\Rightarrow x^2=9\Rightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.$

$m,5\left(x+3\cdot2^3\right)=10^2$

$\Rightarrow5\left(x+24\right)=100$

$\Rightarrow x+24=20$

$\Rightarrow x=-4$

$n,\dfrac{4}{9}-\left(\dfrac{1}{6^2}\right)=\dfrac{2}{3}\left(x-\dfrac{2}{3}\right)^2+\dfrac{5}{12}$

$\Rightarrow\dfrac{2}{3}\left(x-\dfrac{2}{3}\right)^2+\dfrac{5}{12}=\dfrac{4}{9}-\dfrac{1}{36}$

$\Rightarrow\dfrac{2}{3}\left(x-\dfrac{2}{3}\right)^2+\dfrac{5}{12}=\dfrac{5}{12}$

$\Rightarrow\dfrac{2}{3}\left(x-\dfrac{2}{3}\right)^2=0$

$\Rightarrow x-\dfrac{2}{3}=0\Rightarrow x=\dfrac{2}{3}$

#$Urushi\text{☕}$

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Nezuko Kamado

29 tháng 10 2021

Tìm x :

1) $\left(-0,75x+\dfrac{5}{2}\right).\dfrac{4}{7}-\left(-\dfrac{1}{3}\right)=-\dfrac{5}{6}$

2) $\left(4x-9\right)\left(2,5+\dfrac{-7}{3}x\right)=0$

3) $\left|x-\dfrac{3}{4}\right|-\dfrac{1}{2}=0$

4)$\left(\dfrac{3}{5}-\dfrac{2}{3}x\right)^3=\dfrac{-64}{125}$

#Toán lớp 7

Nguyễn Lê Phước Thịnh

29 tháng 10 2021

3: $\left|x-\dfrac{3}{4}\right|-\dfrac{1}{2}=0$

$\Leftrightarrow\left|x-\dfrac{3}{4}\right|=\dfrac{1}{2}$

$\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{3}{4}=\dfrac{1}{2}\\x-\dfrac{3}{4}=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{4}\\x=\dfrac{1}{4}\end{matrix}\right.$

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Dương Thanh Ngân

12 tháng 7 2018

Tìm x:

$\dfrac{x}{-18}=\dfrac{-50}{x};\\ 1\dfrac{1}{3}:\left(-0,08\right)=\dfrac{2}{3}:\left(-0,1x\right);\\ x=\dfrac{a}{b+c}=\dfrac{b}{c+a}=\dfrac{c}{b+a};\\ \dfrac{x^2}{6}=\dfrac{24}{25};\dfrac{x+1}{x-5}=\dfrac{0,5}{0,6};\\ \dfrac{2}{3}x:\dfrac{1}{5}=1\dfrac{1}{3}:\dfrac{1}{4};\\ 1,35:0,2=1,25:0,1x$

#Toán lớp 7

Nguyễn Lê Phước Thịnh

22 tháng 7 2022

a: $\Leftrightarrow x^2=900$

=>x=30 hoặc x=-30

b: $\Leftrightarrow\dfrac{2}{3}:\left(-0.1x\right)=\dfrac{4}{3}:\dfrac{-2}{25}=-\dfrac{4}{3}\cdot\dfrac{25}{2}=-\dfrac{100}{6}=\dfrac{-50}{3}$

=>0,1x=2/3:50/3=2/3x3/50=1/25

=>1/10x=1/25

hay x=1/25:1/10=10/25=2/5

d: $\Leftrightarrow x^2=\dfrac{144}{25}$

=>x=12/5 hoặc x=-12/5

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Lê Phương Linh

1 tháng 11 2023 - olm

Tìm x, biết: a) $\dfrac{2}{3}$x - $\dfrac{1}{2}$x = $\left(-\dfrac{7}{12}\right)$ . $1\dfrac{2}{5}$ b) $\left(\dfrac{1}{5}-\dfrac{3}{2}x\right)^2$ = $\dfrac{9}{4}$ c) (1,25 - $\dfrac{4}{5}$x)3 =...

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#Toán lớp 7

HT.Phong (9A5)

CTVHS

1 tháng 11 2023

a) $\dfrac{2}{3}x-\dfrac{1}{2}x=\left(-\dfrac{7}{12}\right)\cdot1\dfrac{2}{5}$

$\Rightarrow\dfrac{1}{6}x=\left(-\dfrac{7}{12}\right)\cdot\dfrac{7}{5}$

$\Rightarrow\dfrac{1}{6}x=-\dfrac{49}{60}$

$\Rightarrow x=-\dfrac{49}{60}:\dfrac{1}{6}$

$\Rightarrow x=-\dfrac{49}{10}$

b) $\left(\dfrac{1}{5}-\dfrac{3}{2}x\right)^2=\dfrac{9}{4}$

$\Rightarrow\left(\dfrac{1}{5}-\dfrac{3}{2}x\right)^2=\left(\pm\dfrac{3}{2}\right)^2$

+) $\dfrac{1}{5}-\dfrac{3}{2}x=\dfrac{3}{2}$

$\Rightarrow\dfrac{3}{2}x=\dfrac{1}{5}-\dfrac{3}{2}$

$\Rightarrow\dfrac{3}{2}x=-\dfrac{13}{10}$

$\Rightarrow x=-\dfrac{13}{10}:\dfrac{3}{2}$

$\Rightarrow x=-\dfrac{13}{15}$

+) $\left(1,25-\dfrac{4}{5}x\right)^3=-125$

$\Rightarrow\left(\dfrac{5}{4}-\dfrac{4}{5}x\right)^3=\left(-5\right)^3$

$\Rightarrow\dfrac{5}{4}-\dfrac{4}{5}x=-5$

$\Rightarrow\dfrac{4}{5}x=\dfrac{5}{4}+5$

$\Rightarrow\dfrac{4}{5}x=\dfrac{25}{4}$

$\Rightarrow x=\dfrac{25}{4}:\dfrac{4}{5}$

$\Rightarrow x=\dfrac{125}{16}$

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Nguyễn Thị Thương Hoài

Giáo viên VIP

1 tháng 11 2023

a, $\dfrac{2}{3}$$x$ - $\dfrac{1}{2}$$x$ = (- $\dfrac{7}{12}$). 1$\dfrac{2}{5}$

$x$.($\dfrac{2}{3}$ - $\dfrac{1}{2}$) = (- $\dfrac{7}{12}$) . $\dfrac{7}{5}$

$x$. $\dfrac{1}{6}$ = - $\dfrac{49}{60}$

$x$ = - $\dfrac{49}{60}$.6

$x$ = -$\dfrac{49}{10}$

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Lê Thị Ngọc Duyên

20 tháng 8 2017

ĐỀ 1: 1. Tính: a. $\dfrac{7}{23}\left[\left(\dfrac{-8}{6}\right)-\dfrac{45}{18}\right]$ b. $\dfrac{1}{5}:\dfrac{1}{10}-\dfrac{1}{3}\left(\dfrac{6}{5}-\dfrac{9}{4}\right)$ c. $\dfrac{3}{5}.\left(\dfrac{-8}{3}\right)-\dfrac{3}{5}:\left(-6\right)$ d. $\dfrac{1}{2}\left(\dfrac{4}{3}+\dfrac{2}{5}\right)-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)$ e. $\dfrac{6}{7}:\left(\dfrac{3}{26}-\dfrac{3}{13}\right)+\dfrac{6}{7}\left(\dfrac{1}{10}-\dfrac{8}{5}\right)$ 2. Tìm x,...

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#Toán lớp 7

Thanh Trà

20 tháng 8 2017

1.Tính

a.$\dfrac{7}{23}\left[(-\dfrac{8}{6})-\dfrac{45}{18}\right]=\dfrac{7}{23}.-\dfrac{12}{6}=-\dfrac{7}{6}$

b.$\dfrac{1}{5}\div\dfrac{1}{10}-\dfrac{1}{3}(\dfrac{6}{5}-\dfrac{9}{4})=2-(-\dfrac{7}{20})=\dfrac{47}{20}$

c.$\dfrac{3}{5}.(-\dfrac{8}{3})-\dfrac{3}{5}\div(-6)=-\dfrac{3}{2}$

d.$\dfrac{1}{2}.(\dfrac{4}{3}+\dfrac{2}{5})-\dfrac{3}{4}.(\dfrac{8}{9}+\dfrac{16}{3})=-\dfrac{19}{5}$

e.$\dfrac{6}{7}\div(\dfrac{3}{26}-\dfrac{3}{13})+\dfrac{6}{7}.(\dfrac{1}{10}-\dfrac{8}{5})=-\dfrac{61}{7}$

Bài 2

a.$1^2_5x+\dfrac{3}{7}=\dfrac{4}{5}$

$x=\dfrac{13}{49}$

b.$\left|x-1,5\right|=2$

Xảy ra 2 trường hợp

TH1

$x-1,5=2$

$x=3,5$

TH2

$x-1,5=-2$

$x=-0,5$

Vậy $x=3,5$ hoặc $x=-0,5$ .

Ngại làm quá trời ơi,lần sau bn tách ra nhá làm vậy mỏi tay quá.

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Lê Thị Ngọc Duyên

20 tháng 8 2017

Ths bn nhé

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꧁༺ɠấυ❤ƙɑ༻꧂

29 tháng 6 2021

e) $\dfrac{3}{3x}-\dfrac{3}{12}=\dfrac{4}{5}-\left(\dfrac{7}{x}-2\right)$

f) $\dfrac{1}{x-1}+\dfrac{-2}{3}\left(\dfrac{3}{4}-\dfrac{6}{5}\right)=\dfrac{5}{2-2x}$

#Toán lớp 7

Yeutoanhoc

29 tháng 6 2021

`e)3/(3x)-3/12=4/5-(7/x-2)`

`<=>1/x-1/4=4/5-7/x+2`

`<=>8/x=1/4+4/5+2=61/20`

`<=>1/x=61/160`

`<=>x=160/61`

`f)1/(x-1)+(-2)/3(3/4-6/5)=5/(2-2x)`

`<=>1/(x-1)+5/(2x-2)=2/3(3/4-6/5)=-3/10`

`<=>7/(2x-1)=-3/10`

`<=>2x-1=-70/3`

`<=>2x=-67/3`

`<=>x=-67/6`

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꧁༺ɠấυ❤ƙɑ༻꧂

29 tháng 6 2021

ui chào cậu nhá

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Lê Hoàng Khánh

29 tháng 7 2021

2. Tìm xa. $\dfrac{4}{5}-3.\left|x\right|=\dfrac{1}{5}$ b. $4x-\dfrac{1}{2}x+\dfrac{3}{5}x=\dfrac{4}{5}$c. (2x-8)(10-5x)=0 ...

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#Toán lớp 7

Nguyễn Lê Phước Thịnh

29 tháng 7 2021

a) Ta có: $\dfrac{4}{5}-3\left|x\right|=\dfrac{1}{5}$

$\Leftrightarrow3\left|x\right|=\dfrac{4}{5}-\dfrac{1}{5}=\dfrac{3}{5}$

$\Leftrightarrow\left|x\right|=\dfrac{1}{5}$

hay $x\in\left\{\dfrac{1}{5};-\dfrac{1}{5}\right\}$

b) Ta có: $4x-\dfrac{1}{2}x+\dfrac{3}{5}x=\dfrac{4}{5}$

nên $\dfrac{41}{10}x=\dfrac{4}{5}$

hay $x=\dfrac{8}{41}$

c) Ta có: $\left(2x-8\right)\left(10-5x\right)=0$

$\Leftrightarrow\left[{}\begin{matrix}2x-8=0\\10-5x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=8\\5x=10\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=2\end{matrix}\right.$

d) Ta có: $\dfrac{3}{4}+\dfrac{1}{4}\left|2x-1\right|=\dfrac{7}{2}$

$\Leftrightarrow\dfrac{1}{4}\left|2x-1\right|=\dfrac{7}{2}-\dfrac{3}{4}=\dfrac{14}{4}-\dfrac{3}{4}=\dfrac{11}{4}$

$\Leftrightarrow\left|2x-1\right|=11$

$\Leftrightarrow\left[{}\begin{matrix}2x-1=11\\2x-1=-11\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=12\\2x=-10\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-5\end{matrix}\right.$

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Thầy Đức Anh

Giáo viên VIP

27 tháng 4 2022 - olm

Tìm $x$, biết :
a) $\left(\dfrac{1}{2}+1,5\right) \cdot x=\dfrac{1}{5}$
b) $\left(-1 \dfrac{3}{5}+x\right): \dfrac{12}{13}=2 \dfrac{1}{6}$
c) $\left(x: 2 \dfrac{1}{3}\right) \cdot \dfrac{1}{7}=\dfrac{-3}{8}$
d) $\dfrac{-4}{7} \cdot x+\dfrac{7}{5}=\dfrac{1}{8}:\left(-1 \dfrac{2}{3}\right)$

#Toán lớp 7

Yen Nhi

21 tháng 6 2022

$a)\left(\dfrac{1}{2}+1,5\right)x=\dfrac{1}{5}$

$\Rightarrow2x=\dfrac{1}{5}$

$\Rightarrow x=\dfrac{1}{10}$

$b)\left(-1\dfrac{3}{5}+x\right):\dfrac{12}{13}=2\dfrac{1}{6}$

$\Leftrightarrow-\dfrac{8}{5}+x=\dfrac{13}{6}.\dfrac{12}{13}$

$\Leftrightarrow-\dfrac{8}{5}+x=2$

$\Leftrightarrow x=\dfrac{18}{5}$

$c)\left(x:2\dfrac{1}{3}\right).\dfrac{1}{7}=-\dfrac{3}{8}$

$\Leftrightarrow x:\dfrac{7}{3}=-\dfrac{3}{8}:\dfrac{1}{7}$

$\Leftrightarrow x=-\dfrac{21}{8}.\dfrac{7}{3}$

$\Leftrightarrow x=-\dfrac{49}{8}$

$d)-\dfrac{4}{7}x+\dfrac{7}{5}=\dfrac{1}{8}:\left(-1\dfrac{2}{3}\right)$

$\Leftrightarrow-\dfrac{4}{7}x+\dfrac{7}{5}=-\dfrac{3}{40}$

$\Leftrightarrow-\dfrac{4}{7}x=-\dfrac{59}{40}$

$\Leftrightarrow x=\dfrac{413}{160}$

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TINH

13 tháng 7 2022

a) $\left(\dfrac{1}{2}+1,5\right) \cdot x=\dfrac{1}{5}$

$\cdot x=\dfrac{1}{5}$

$x=\dfrac{1}{5}: 2$

$x=\dfrac{1}{10}$
b) $\left(-1 \dfrac{3}{5}+x\right): \dfrac{12}{13}=2 \dfrac{1}{6}$

$\dfrac{3}{5}+x=\dfrac{13}{6} \cdot \dfrac{12}{13}$
$\dfrac{3}{5}$

$\dfrac{3}{5}$
c) $\left(x: 2 \dfrac{1}{3}\right) \cdot \dfrac{1}{7}=\dfrac{-3}{8}$

$\cdot \dfrac{3}{7} \cdot \dfrac{1}{7}=\dfrac{-3}{8}$

$x=\dfrac{-3}{8}: \dfrac{3}{49}$
$x=\dfrac{-49}{8}=-6 \dfrac{1}{8}$
d) $\dfrac{-4}{7} \cdot x+\dfrac{7}{5}=\dfrac{1}{8}:\left(-1 \dfrac{2}{3}\right)$

$\dfrac{-4}{7} x+\dfrac{7}{5}=\dfrac{1}{8} \cdot \dfrac{-3}{5}$
$-\dfrac{4}{7} x=\dfrac{-3}{40}-\dfrac{7}{5} \\ x=\dfrac{-59}{40}: \dfrac{-4}{7}=\dfrac{413}{160}=2 \dfrac{93}{160}$

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ĐOÀN THỊ MINH HIỀN

26 tháng 9 2021

$b,\dfrac{x}{2}-\left(\dfrac{3x}{5}-\dfrac{13}{5}\right)=-\left(\dfrac{7}{5}+\dfrac{7}{10}.x\right)$

$c,\dfrac{2x-3}{3}+\dfrac{-3}{2}=\dfrac{5-3x}{6}-\dfrac{1}{3}$

$d,\dfrac{2}{3x}-\dfrac{3}{12}=\dfrac{4}{5}-\left(\dfrac{7}{x}-2\right)$

$e,2\left(x-1\right)=\left(x-1\right)^2$

#Toán lớp 7

Nguyễn Hoàng Minh

26 tháng 9 2021

$b,\Rightarrow\dfrac{x}{2}-\dfrac{3x}{5}-\dfrac{13}{5}=-\dfrac{7}{5}-\dfrac{7x}{10}\\ \Rightarrow\dfrac{1}{2}x-\dfrac{3}{5}x+\dfrac{7}{10}x=\dfrac{6}{5}\\ \Rightarrow\dfrac{3}{5}x=\dfrac{6}{5}\Rightarrow x=2\\ c,\Rightarrow\dfrac{2x-3}{3}-\dfrac{5-3x}{6}=-\dfrac{1}{3}+\dfrac{3}{2}=\dfrac{7}{6}\\ \Rightarrow\dfrac{4x-6-5+3x}{6}=\dfrac{7}{6}\\ \Rightarrow7x-11=7\Rightarrow x=\dfrac{18}{7}\\ d,\Rightarrow\dfrac{2}{3x}+\dfrac{7}{x}=\dfrac{4}{5}+2+\dfrac{3}{12}=\dfrac{61}{20}\\ \Rightarrow\dfrac{23}{3x}=\dfrac{61}{20}\\ \Rightarrow183x=460\\ \Rightarrow x=\dfrac{460}{183}\\ e,\Rightarrow2\left(x-1\right)-\left(x-1\right)^2=0\\ \Rightarrow\left(x-1\right)\left(2-x+1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=1\\x=3\end{matrix}\right.$

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Nguyễn Lê Phước Thịnh

26 tháng 9 2021

e: Ta có: $\left(x-1\right)^2=2\left(x-1\right)$

$\Leftrightarrow\left(x-1\right)\left(x-3\right)=0$

$\Leftrightarrow\left[{}\begin{matrix}x=1\\x=3\end{matrix}\right.$

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