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

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

NH

Nguyễn Hải Đăng

20 tháng 1 2022

Tìm x:

a) $\dfrac{x}{4}=\dfrac{4}{x}$

b) $\dfrac{x+7}{15}=-\dfrac{24}{36}$

c) $\dfrac{x+1}{8}=\dfrac{2}{x+1}$

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

3

NH

Nguyễn Huy Tú ( ✎﹏IDΣΛ亗 )

20 tháng 1 2022

a, đk x khác 0

<=> x^2 = 16 <=> x = 4 ; x = -4 (tm)

b, <=> 36x +252 = -360 <=> x = -17

c. đk x khác -1

<=> (x+1)^2 = 16

TH1 : x + 1 = 4 <=> x = 3 (tm)

TH2 : x + 1 = -4 <=> x = -5 (tm)

d, đk x khác 1/2

<=> (2x-1)^2 = 81

TH1 : 2x - 1 = 9 <=> x = 5 (tm)

TH2 : 2x - 1 = -9 <=> x = -4 (tm)

NL

Nguyễn Lê Phước Thịnh

20 tháng 1 2022

a: $\Leftrightarrow x^2=16$

hay $x\in\left\{4;-4\right\}$

b: =>x+7/15=-2/3

=>x+7=-10

hay x=-17

c: $\Leftrightarrow\left(x+1\right)^2=16$

$\Leftrightarrow x+1\in\left\{4;-4\right\}$

hay $x\in\left\{3;-5\right\}$

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

LN

Lê Ngọc Anh

8 tháng 3 2022

2

HP

hưng phúc

8 tháng 3 2022

$a.x+\dfrac{1}{6}=-\dfrac{3}{8}$

$\Leftrightarrow x=-\dfrac{13}{24}$

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

$\Leftrightarrow2-\dfrac{3}{4}+x=\dfrac{7}{12}$

$\Leftrightarrow x=-\dfrac{2}{3}$

$c.\dfrac{1}{2}x+\dfrac{1}{8}x=\dfrac{3}{4}$

$\Leftrightarrow\dfrac{5}{8}x=\dfrac{3}{4}$

$\Leftrightarrow x=\dfrac{6}{5}$

$d.75\%-1\dfrac{1}{2}+0,5:\dfrac{5}{12}-\left(\dfrac{-1}{2}\right)^2$

$=\dfrac{75}{100}-\dfrac{3}{2}+\dfrac{1}{2}:\dfrac{5}{12}-\dfrac{1}{4}$

$=-\dfrac{3}{4}+\dfrac{6}{5}-\dfrac{1}{4}$

$=\dfrac{1}{5}$

DC

dâu cute

8 tháng 3 2022

a) $x+\dfrac{1}{6}=\dfrac{-3}{8}$

$x=\dfrac{-3}{8}-\dfrac{1}{6}$

$x=\dfrac{-13}{24}$

vậy x =....

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

$\dfrac{3}{4}-x=2-\dfrac{7}{12}$

$\dfrac{3}{4}-x=\dfrac{17}{12}$

$x=\dfrac{3}{4}-\dfrac{17}{12}$

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

vậy x =....

TD

Thầy Đức Anh

Giáo viên VIP

27 tháng 4 2022

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

13

YN

Yen Nhi

21 tháng 6 2022

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

T

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

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

Tìm x biết: a) $\left(x-\dfrac{1}{2}\right)\left(-3-\dfrac{x}{2}\right)=0$ b) $x-\dfrac{1}{8}=\dfrac{5}{8}$c) $-\dfrac{1}{2}-\left(\dfrac{3}{2}+x\right)=-2$ ...

NH

Nguyễn Hữu Bình

18 tháng 4 2022

1

O

★彡✿ทợท彡★

18 tháng 4 2022

a) $\left(x-\dfrac{1}{2}\right)\left(-3-\dfrac{x}{2}\right)=0$

Th1 : $x-\dfrac{1}{2}=0$

$x=0+\dfrac{1}{2}$

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

Th2 : $-3-\dfrac{x}{2}=0$

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

$x=\left(-3\right)\cdot2$

$x=-6$

Vậy $x$ = $\left(\dfrac{1}{2};-6\right)$

b) $x-\dfrac{1}{8}=\dfrac{5}{8}$

$x=\dfrac{5}{8}+\dfrac{1}{8}$

$x=\dfrac{3}{4}$

c) $-\dfrac{1}{2}-\left(\dfrac{3}{2}+x\right)=-2$

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

$\dfrac{3}{2}+x=\dfrac{3}{2}$

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

$x=0$

d) $x+\dfrac{1}{3}=\dfrac{-12}{5}\cdot\dfrac{10}{6}$

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

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

$x=-\dfrac{13}{3}$

Tìm x, biết: a) $\dfrac{1}{20}$ - (x - $\dfrac{8}{5}$) = $\dfrac{1}{10}$ b) $\dfrac{7}{4}$ - (x + $\dfrac{5}{3}$) = $\dfrac{-12}{5}$ c) x - [$\dfrac{17}{2}$ - $\left(\dfrac{-3}{7}+\dfrac{5}{3}\right)$]...

LP

Lê Phương Linh

1 tháng 11 2023

#Toán lớp 7

2

NT

Nguyễn Thùy Dương

1 tháng 11 2023

KV

Kiều Vũ Linh

1 tháng 11 2023

a) 1/20 - (x - 8/5) = 1/10

x - 8/5 = 1/20 - 1/10

x - 8/5 = -1/20

x = -1/20 + 8/5

x = 31/20

b) 7/4 - (x + 5/3) = -12/5

x + 5/3 = 7/4 + 12/5

x + 5/3 = 83/20

x = 83/20 - 5/3

x = 149/60

c) x - [17/2 - (-3/7 + 5/3)] = -1/3

x - (17/2 - 26/21) = -1/3

x - 305/42 = -1/3

x = -1/3 + 305/42

x = 97/14

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 =...

LP

Lê Phương Linh

1 tháng 11 2023

#Toán lớp 7

2

H9

HT.Phong (9A5)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Đúng(2)

NT

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

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

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,$\dfrac{6}{2x+1}=\dfrac{2}{7}$

⇒$\dfrac{6}{2x+1}=\dfrac{6}{21}$

⇒$2x+1=21$

$2x=21-1$

$2x=20$

⇒$x=10$

Đúng(3)

TN

Trần Nguyễn Phương Thảo

VIP

11 tháng 7 2023

Tìm x:

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

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

c) $\dfrac{x}{3}=\dfrac{12}{x}$

Giúp với!

a) (X-2)(x+3)-3(4x-2)=(x-4)$^{^{ }2}$b) $\dfrac{2x^2+1}{8}-\dfrac{7x-2}{12}=\dfrac{x^2-1}{4}-\dfrac{x-3}{6}$c) $x-\dfrac{2x-2}{5}+\dfrac{x+8}{6}=7+\dfrac{x-1}{3}$d) $\left(2x+5\right)^2=\left(x+2\right)^2$e) $x^2-5+6=0$g) $2x^3+6x^2=x^2+3x$h) $\left(x+\dfrac{1}{2}\right)^2+2\left(x+\dfrac{1}{x}\right)-8=0$mọi người giúp e với...

5

DD

Di Di

11 tháng 7 2023

$\dfrac{5}{4}+\left(2x-\dfrac{1}{2}\right)=\dfrac{5}{6}\\ =>2x-\dfrac{1}{2}=\dfrac{5}{6}-\dfrac{5}{4}\\ =>2x-\dfrac{1}{2}=\dfrac{10}{12}-\dfrac{15}{12}\\ =>2x-\dfrac{1}{2}=-\dfrac{5}{12}\\ =>2x=-\dfrac{5}{12}+\dfrac{1}{2}\\ =>2x=-\dfrac{5}{12}+\dfrac{6}{12}\\ =>2x=\dfrac{1}{12}\\ =>x=\dfrac{1}{12}:2\\ =>x=\dfrac{1}{12}\cdot\dfrac{1}{2}\\ =>x=\dfrac{1}{24}$

__

$\dfrac{3}{2}-\left(x+\dfrac{1}{4}\right)=\dfrac{5}{8}\\ =>x+\dfrac{1}{4}=\dfrac{3}{2}-\dfrac{5}{8}\\ =>x+\dfrac{1}{4}=\dfrac{12}{8}-\dfrac{5}{8}\\ =>x+\dfrac{1}{4}=\dfrac{7}{8}\\ =>x=\dfrac{7}{8}-\dfrac{1}{4}\\ =>x=\dfrac{7}{8}-\dfrac{2}{8}\\ =>x=\dfrac{5}{8}$

__

$\dfrac{x}{3}=\dfrac{12}{x}\\ =>x^2=3\cdot12\\ =>x^2=36\\ =>x^2=6^2\\ =>x=\pm6$

Đúng(2)

VN

Võ Ngọc Phương

VIP

11 tháng 7 2023

Tìm x:

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

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

$=>2x-\dfrac{1}{2}=\dfrac{-5}{12}$

$=>2x=\dfrac{-5}{12}+\dfrac{1}{2}$

$=>2x=\dfrac{1}{12}$

$=>x=\dfrac{1}{12}:2$

$=>x=\dfrac{1}{24}$

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

$=>x+\dfrac{1}{4}=\dfrac{3}{2}-\dfrac{5}{8}$

$=>x+\dfrac{1}{4}=\dfrac{7}{8}$

$=>x=\dfrac{7}{8}-\dfrac{1}{4}$

$=>x=\dfrac{5}{8}$

c) $\dfrac{x}{3}=\dfrac{12}{x}$

Ta có: $x.x=3.12$

$\Rightarrow x^2=36$

Vậy x = 6 hoặc x = -6

Chúc bạn học tốt

Đúng(4)

TL

Thùyy Lynhh

24 tháng 8 2021

#Toán lớp 8

4

NH

Nguyễn Hoàng Minh

24 tháng 8 2021

$a,\left(x-2\right)\left(x-3\right)-3\left(4x-2\right)=\left(x-4\right)^2\\ \Leftrightarrow x^2-5x+6-12x+6=x^2-8x+16\\ \Leftrightarrow-9x-4=0\\ \Leftrightarrow x=-\dfrac{4}{9}$

$b,\dfrac{2x^2+1}{8}-\dfrac{7x-2}{12}=\dfrac{x^2-1}{4}-\dfrac{x-3}{6}\\ \Leftrightarrow6x^2+3-14x+4=6x^2-6-4x+12\\ \Leftrightarrow10x=1\\ \Leftrightarrow x=\dfrac{1}{10}$

$c,x-\dfrac{2x-2}{5}+\dfrac{x+8}{6}=7+\dfrac{x-1}{3}\\ \Leftrightarrow30x-12x+12+5x+40=210+10x-10\\ \Leftrightarrow13x=148\\ \Leftrightarrow x=\dfrac{148}{13}$

Đúng(2)

NH

Nguyễn Hoàng Minh

24 tháng 8 2021

$d,\left(2x+5\right)^2=\left(x+2\right)^2\\ \Leftrightarrow\left(2x+5\right)^2-\left(x+2\right)^2=0\\ \Leftrightarrow\left(2x+5-x-2\right)\left(2x+5+x+2\right)=0\\ \Leftrightarrow\left(x+3\right)\left(3x+7\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-3\\x=-\dfrac{7}{3}\end{matrix}\right.$

$e,x^2-5x+6=0\\ \Leftrightarrow\left(x-2\right)\left(x-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=3\end{matrix}\right.$

$g,2x^3+6x^2=x^2+3x\\ \Leftrightarrow2x^2\left(x+3\right)-x\left(x+3\right)=0\\ \Leftrightarrow x\left(2x-1\right)\left(x+3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{1}{2}\\x=-3\end{matrix}\right.$

$h,\left(x+\dfrac{1}{x}\right)^2+2\left(x+\dfrac{1}{x}\right)-8=0\left(x\ne0\right)$

Đặt $x+\dfrac{1}{x}=t$, pt trở thành:

$t^2+2t-8=0\\ \Leftrightarrow\left(t-2\right)\left(t+4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}t=2\\t=-4\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{x}=2\\x+\dfrac{1}{x}=-4\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x^2+1-2x=0\\x^2+1+4x=0\left(1\right)\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}\left(x-1\right)^2=0\\\Delta\left(1\right)=16-4=12>0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=1\\\left[{}\begin{matrix}x=-2+\sqrt{3}\\x=-2-\sqrt{3}\end{matrix}\right.\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=1\\x=-2+\sqrt{3}\\x=-2-\sqrt{3}\end{matrix}\right.$

Tick plzz