1:Tính a) $\left(\dfrac{1}{7}.x-\dfrac{2}{7}\right).\left(\dfrac{-1}{5}.x-\dfrac{2}{5}\right)=0$ b) $\dfrac{1}{6}.x \dfrac{1}{10}.x-\dfrac{4}{5}.x 1=0$ 2:So sánh: a) A=\(\left(\dfrac{-46}{51}....

1

NH

Nguyễn Huỳnh Bảo Trân

7 tháng 4 2017

a) (1/7.x-2/7).(-1/5.x-2/5)=0

=> 1/7.x-2/7=0hoặc-1/5.x-2/5=0

*1/7.x-2/7=0

1/7.x=0+2/7

1/7.x=2/7

x=2/7:1/7

x=2

b)1/6.x+1/10.x-4/5.x+1=0

(1/6+1/10-4/5).x+1=0

(1/6+1/10-4/5).x=0-1

(1/6+1/10-4/5).x=-1

(-8/15).x=-1

x=-1:(-8/15) =15/8

KJ

❖ Khang/GD❄ 『ʈєɑɱ❖Hoàng๖ۣۜGia☆』

28 tháng 2 2022

Tìm x biết:

$a,\left(x-\dfrac{3}{4}\right)+50\%=\dfrac{1}{6}$

$b,\dfrac{1}{2}x-\dfrac{5}{6}x=\dfrac{7}{2}$

$c,\left(4-x\right)\left(3x+5\right)=0$

$d,\dfrac{x}{16}=\dfrac{50}{32}$

$e,\left(2x-3\right)+\dfrac{3}{2}=-\dfrac{1}{4}$

1

NL

Nguyễn Lê Phước Thịnh

28 tháng 2 2022

a: =>x-3/4=1/6-1/2=1/6-3/6=-2/6=-1/3

=>x=-1/3+3/4=-4/12+9/12=5/12

b: =>x(1/2-5/6)=7/2

=>-1/3x=7/2

hay x=-21/2

c: (4-x)(3x+5)=0

=>4-x=0 hoặc 3x+5=0

=>x=4 hoặc x=-5/3

d: x/16=50/32

=>x/16=25/16

hay x=25

e: =>2x-3=-1/4-3/2=-1/4-6/4=-7/4

=>2x=-7/4+3=5/4

hay x=5/8

NK

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

1

NL

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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KJ

❖ Khang/GD❄ 『ʈєɑɱ❖Hoàng๖ۣۜGia☆』

29 tháng 1 2022

Tìm x...

2

KS

Kudo Shinichi AKIRA^_^

29 tháng 1 2022

Chia nhỏ ra

NL

Nguyễn Lê Phước Thịnh

29 tháng 1 2022

a: =>1/2x=7/2-2/3=21/6-4/6=17/6

=>x=17/3

b: =>2/3:x=-7-1/3=-22/3

=>x=2/3:(-22/3)=-1/11

c: =>1/3x+2/5x-2/5=0

=>11/15x=2/5

hay x=6/11

d: =>2x-3=0 hoặc 6-2x=0

=>x=3/2 hoặc x=3

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K

Kfkfj

15 tháng 4 2017

tìm x:

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

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

c) $x.3\dfrac{1}{4}+\left(\dfrac{-7}{6}\right).x-1\dfrac{2}{3}=\dfrac{5}{12}$

d) $5\dfrac{8}{17}:x+\left(-\dfrac{4}{17}\right):x+3\dfrac{1}{7}:17\dfrac{1}{3}=\dfrac{4}{11}$

1

NL

Nguyễn Lê Phước Thịnh

15 tháng 5 2022

a: (x+1/2)(2/3-2x)=0

=>x+1/2=0 hoặc 2/3-2x=0

=>x=-1/2 hoặc x=1/3

b: undefined

c: $\Leftrightarrow x\cdot\left(\dfrac{13}{4}-\dfrac{7}{6}\right)=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{5}{12}+\dfrac{20}{12}=\dfrac{25}{12}$

$\Leftrightarrow x=\dfrac{25}{12}:\dfrac{39-14}{12}=\dfrac{25}{25}=1$

So sánh $\dfrac{9}{170};\dfrac{9}{230};\dfrac{53}{144}$ Số nguyên $x$ thỏa mãn $\left(\dfrac{3}{4}-\dfrac{2}{3}\right)+\dfrac{5}{6}\le x\le\dfrac{4}{5}-\left(\dfrac{3}{10}-\dfrac{5}{4}\right)$A. $x=1$ B. $x=0$ C. $x=2$ D. $x\in\left\{0;1\right\}$ EM CẦN GẤP...

HG

Hương Giang Vũ

5 tháng 3 2022

Cần giúp nhanh vsBài 1. Tìm xa) $\left|x+\dfrac{7}{4}\right|=\dfrac{1}{2}$b) $\left|2x+1\right|-\dfrac{2}{5}=\dfrac{1}{3}$c) $3x.\left(x+\dfrac{2}{3}\right)=0$d) $x+\dfrac{1}{3}=\dfrac{2}{5}-\left(-\dfrac{1}{3}\right)$Bài 2. Tính...

1

TH

Thanh Hoàng Thanh

5 tháng 3 2022

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NQ

Nguyễn Quý Trung

25 tháng 7 2021

#Toán lớp 7

5

AH

Akai Haruma

Giáo viên

25 tháng 7 2021

Bài 1:

a.

$|x+\frac{7}{4}|=\frac{1}{2}$

$\Leftrightarrow \left[\begin{matrix} x+\frac{7}{4}=\frac{1}{2}\\ x+\frac{7}{4}=-\frac{1}{2}\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x=\frac{-5}{4}\\ x=\frac{-9}{4}\end{matrix}\right.$

b. $|2x+1|-\frac{2}{5}=\frac{1}{3}$
$|2x+1|=\frac{1}{3}+\frac{2}{5}$

$|2x+1|=\frac{11}{15}$

$\Leftrightarrow \left[\begin{matrix} 2x+1=\frac{11}{15}\\ 2x+1=\frac{-11}{15}\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x=\frac{-2}{15}\\ x=\frac{-13}{15}\end{matrix}\right.$

c.

$3x(x+\frac{2}{3})=0$

$\Leftrightarrow \left[\begin{matrix} 3x=0\\ x+\frac{2}{3}=0\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x=0\\ x=\frac{-3}{2}\end{matrix}\right.$

d.

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

$\Leftrightarrow x=\frac{2}{5}$

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AH

Akai Haruma

Giáo viên

25 tháng 7 2021

Nguyễn Quý Trung:

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

Bạn bớt 2 vế đi 1/3 thì $x=\dfrac{2}{5}$

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ZZ

zed zed

8 tháng 10 2017

1 tìm x
a,$\dfrac{1}{4}x-\left|-\dfrac{3}{10}\right|$
$\left(\dfrac{2}{5}-\dfrac{7}{10}x\right):1\dfrac{2}{3}=\dfrac{-3}{4}$
$\dfrac{7}{16}:\left(\dfrac{x}{4}+\dfrac{9}{2}\right)-1\dfrac{5}{6}=0$

#Toán lớp 7

1

NL

Nguyễn Lê Phước Thịnh

29 tháng 5 2022

b: $\left(\dfrac{2}{5}-\dfrac{7}{10}x\right):\dfrac{5}{3}=-\dfrac{3}{4}$

$\Leftrightarrow\dfrac{2}{5}-\dfrac{7}{10}x=\dfrac{-3}{4}\cdot\dfrac{5}{3}=\dfrac{-5}{4}$

$\Leftrightarrow x\cdot\dfrac{7}{10}=\dfrac{2}{5}+\dfrac{5}{4}=\dfrac{8+25}{20}=\dfrac{33}{20}$

$\Leftrightarrow x=\dfrac{33}{20}:\dfrac{7}{10}=\dfrac{33}{20}\cdot\dfrac{10}{7}=\dfrac{33}{14}$

c: $\dfrac{7}{16}:\left(\dfrac{1}{4}x+\dfrac{9}{2}\right)-\dfrac{11}{6}=0$

$\Leftrightarrow\dfrac{7}{16}:\left(\dfrac{1}{4}x+\dfrac{9}{2}\right)=\dfrac{11}{6}$

$\Leftrightarrow x\cdot\dfrac{1}{4}+\dfrac{9}{2}=\dfrac{11}{6}:\dfrac{7}{16}=\dfrac{88}{21}$

$\Leftrightarrow x\cdot\dfrac{1}{4}=\dfrac{88}{21}-\dfrac{9}{2}=-\dfrac{13}{42}$

hay $x=-\dfrac{26}{21}$

1. $\dfrac{5\left(x-1\right)+2}{6}-\dfrac{7x-1}{4}=\dfrac{2\left(2x+1\right)}{7}-5$ 2. $x-\dfrac{3\left(x+30\right)}{15}-24\dfrac{1}{2}=\dfrac{7x}{10}-\dfrac{2\left(10x+2\right)}{5}$ 3. $14\dfrac{1}{2}-\dfrac{2\left(x+3\right)}{5}=\dfrac{3x}{2}-\dfrac{2\left(x-7\right)}{3}$ 4. $\dfrac{x+1}{3}+\dfrac{3\left(2x+1\right)}{4}=\dfrac{2x+3\left(x+1\right)}{6}+\dfrac{7+12x}{12}$ 5. $\dfrac{3\left(2x-1\right)}{4}-\dfrac{3x+1}{10}+1=\dfrac{2\left(3x+2\right)}{5}$ 6....

WH

원회으Won Hoe Eu

13 tháng 2 2019

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

#Toán lớp 8

0

NH

Nguyễn Hữu Bình

18 tháng 4 2022