tim x\dfrac{5}{6}x-\dfrac{3}{4}=\dfrac{-1}{4} \dfrac{2}{3}65x−43=4−1 32-1\dfrac{1}{2}-\dfrac{2}{3}x=\dfrac{5}{6}-\left(\dfrac{-2}{5}\right)−121−32x=65−(5−2)\left(\dfrac{4}{5}:x 1,5\right):\dfr...

0

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

AT

Anh Thư Trần

21 tháng 1 2021

$\left\{1\dfrac{3}{4}-\dfrac{4}{6}\right\}:\left\{1\dfrac{1}{5}+2\dfrac{2}{5}+\dfrac{1}{5}\right\}< x< 1\dfrac{1}{5}.1\dfrac{3}{4}+3\dfrac{2}{11}:2\dfrac{3}{121}$ với x là số tự nhiên

1

NG

Nguyễn Giang

25 tháng 1 2021

$\left(1\dfrac{3}{4}-\dfrac{4}{6}\right):\left(1\dfrac{1}{5}+2\dfrac{2}{5}+\dfrac{1}{5}\right)< x< 1\dfrac{1}{5}.1\dfrac{1}{4}+3\dfrac{2}{11}:2\dfrac{3}{121}$

$\Leftrightarrow\left(\dfrac{7}{4}-\dfrac{4}{6}\right):\left(\dfrac{6}{5}+\dfrac{12}{5}+\dfrac{1}{5}\right)< x< \dfrac{6}{5}.\dfrac{5}{4}+\dfrac{35}{11}:\dfrac{245}{121}$ $\Leftrightarrow\left(\dfrac{21}{12}-\dfrac{8}{12}\right):\dfrac{19}{5}< x< \dfrac{3}{2}+\dfrac{35}{11}.\dfrac{121}{245}$ $\Leftrightarrow\dfrac{13}{12}.\dfrac{5}{19}< x< \dfrac{3}{2}+\dfrac{2}{7}$ $\Leftrightarrow\dfrac{65}{228}< x< \dfrac{21}{14}+\dfrac{4}{14}$ $\Leftrightarrow\dfrac{65}{228}< x< \dfrac{25}{14}$ $\Leftrightarrow x=1$

HT

Hoàng Thúy An

19 tháng 9 2017

tim x

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

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

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

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

giup minh nhe minh dang can gap

1

RT

Rain Tờ Rym Te

19 tháng 9 2017

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

$\Leftrightarrow\dfrac{5}{6}x=\dfrac{7}{6}$

$\Rightarrow x=\dfrac{7}{5}$

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

$\Leftrightarrow\dfrac{2}{3}x=-\dfrac{41}{15}$

$\Rightarrow x=-\dfrac{41}{10}$

c) $\left(\dfrac{4}{5}:x+1,5\right):\dfrac{2}{3}=-1,5$

$\Leftrightarrow\dfrac{8+15x}{10x}.\dfrac{3}{2}=\dfrac{-3}{2}$

$\Leftrightarrow\dfrac{24+45x}{20x}=\dfrac{-3}{2}$

$\Leftrightarrow-60x=48+90x$

$\Rightarrow x=-0,32$

d) $\dfrac{4}{3}x-\dfrac{2}{3}=\dfrac{1}{4}-x$

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

$\Rightarrow16x-8=3-12x$

$\Rightarrow x=\dfrac{11}{28}$

HQ

Hạ Quỳnh

20 tháng 12 2020

Bài 2:Tìm x...

1

NL

Nguyễn Lê Phước Thịnh

20 tháng 12 2020

a) Ta có: $\dfrac{1}{7}+x=-\dfrac{2}{3}$

$\Leftrightarrow x=-\dfrac{2}{3}-\dfrac{1}{7}=\dfrac{-14}{21}-\dfrac{3}{21}$

hay $x=-\dfrac{17}{21}$

Vậy: $x=-\dfrac{17}{21}$

b) Ta có: $\dfrac{-2}{3}:x=\dfrac{-5}{6}$

$\Leftrightarrow x=\dfrac{-2}{3}:\dfrac{-5}{6}=\dfrac{-2}{3}\cdot\dfrac{6}{-5}=\dfrac{-12}{-15}=\dfrac{4}{5}$

Vậy: $x=\dfrac{4}{5}$

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

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

$\Leftrightarrow-2x=\dfrac{8}{5}-\dfrac{3}{5}=1$

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

Vậy: $x=-\dfrac{1}{2}$

d) Ta có: $\dfrac{3}{4}+\dfrac{2}{5}x=\dfrac{29}{60}$

$\Leftrightarrow x\cdot\dfrac{2}{5}=\dfrac{29}{60}-\dfrac{3}{4}=\dfrac{29}{60}-\dfrac{45}{60}=\dfrac{-16}{60}=\dfrac{-4}{15}$

hay $x=\dfrac{-4}{15}:\dfrac{2}{5}=\dfrac{-4}{15}\cdot\dfrac{5}{2}=\dfrac{-20}{30}=-\dfrac{2}{3}$

Vậy: $x=-\dfrac{2}{3}$

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

$\Leftrightarrow\dfrac{1}{4}:x=\dfrac{2}{5}-\dfrac{3}{4}=\dfrac{8}{20}-\dfrac{15}{20}=\dfrac{-7}{20}$

hay $x=-\dfrac{1}{4}:\dfrac{7}{20}=\dfrac{-1}{4}\cdot\dfrac{20}{7}=\dfrac{-20}{28}=\dfrac{-5}{7}$

Vậy: $x=-\dfrac{5}{7}$

f) Ta có: $\dfrac{11}{12}-\left(\dfrac{2}{5}+x\right)=\dfrac{2}{3}$

$\Leftrightarrow-x+\dfrac{11}{12}-\dfrac{2}{5}-\dfrac{2}{3}=0$

$\Leftrightarrow-x+\dfrac{55}{60}-\dfrac{24}{60}-\dfrac{40}{60}=0$

$\Leftrightarrow-x-\dfrac{9}{60}=0$

$\Leftrightarrow-x=\dfrac{9}{60}=\dfrac{3}{20}$

hay $x=-\dfrac{3}{20}$

Vậy: $x=-\dfrac{3}{20}$

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

$\Leftrightarrow\left|x+\dfrac{1}{3}\right|=\dfrac{-1}{2}+4=\dfrac{-1}{2}+\dfrac{8}{2}=\dfrac{7}{2}$

$\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{3}=\dfrac{7}{2}\\x+\dfrac{1}{3}=-\dfrac{7}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}-\dfrac{1}{3}=\dfrac{21}{6}-\dfrac{2}{6}=\dfrac{19}{6}\\x=-\dfrac{7}{2}-\dfrac{1}{3}=\dfrac{-21}{6}-\dfrac{2}{6}=\dfrac{-23}{6}\end{matrix}\right.$

Vậy: $x\in\left\{\dfrac{19}{6};-\dfrac{23}{6}\right\}$

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HQ

Hạ Quỳnh

20 tháng 12 2020

cảm ơn cậu cutee gì đó ơi nha

Giải phương trình$a,\dfrac{x-3}{5}=6-\dfrac{1-2x}{3}$$b,\dfrac{3x-2}{6}-5=\dfrac{3-2\left(x+7\right)}{4}$$c,3\left(x-1\right)+3=5x$$d,\dfrac{x+1}{100}+\dfrac{x+2}{99}=\dfrac{x+3}{98}+\dfrac{x+4}{97}$$e,\dfrac{59-x}{41}+\dfrac{57-x}{43}+\dfrac{55-x}{45}+\dfrac{53-x}{47}=-4$$f,\dfrac{x-90}{10}+\dfrac{x-76}{12}+\dfrac{x-58}{14}+\dfrac{x-36}{16}+\dfrac{x-15}{17}=15$Em mới học về pt nên chưa quen lắm mọi người giúp e với ạ !Nguyễn Việt Lâm Quản lý ...

KH

Kamato Heiji

23 tháng 1 2021

#Toán lớp 8

3

NL

Nguyễn Lê Phước Thịnh

23 tháng 1 2021

a) Ta có: $\dfrac{x-3}{5}=6-\dfrac{1-2x}{3}$

$\Leftrightarrow\dfrac{3\left(x-3\right)}{15}=\dfrac{90}{15}-\dfrac{5\left(1-2x\right)}{15}$

$\Leftrightarrow3x-9=90-5+10x$

$\Leftrightarrow3x-9=10x+85$

$\Leftrightarrow3x-10x=85+9$

$\Leftrightarrow-7x=94$

hay $x=-\dfrac{94}{7}$

Vậy: $S=\left\{-\dfrac{94}{7}\right\}$

b) Ta có: $\dfrac{3x-2}{6}-5=\dfrac{3-2\left(x+7\right)}{4}$

$\Leftrightarrow\dfrac{2\left(3x-2\right)}{12}-\dfrac{60}{12}=\dfrac{3\left(3-2x-14\right)}{12}$

$\Leftrightarrow6x-4-60=9-6x-42$

$\Leftrightarrow6x-64=-6x-33$

$\Leftrightarrow6x+6x=-33+64$

$\Leftrightarrow12x=31$

hay $x=\dfrac{31}{12}$

Vậy: $S=\left\{\dfrac{31}{12}\right\}$

c) Ta có: $3\left(x-1\right)+3=5x$

$\Leftrightarrow3x-3+3=5x$

$\Leftrightarrow3x-5x=0$

$\Leftrightarrow-2x=0$

hay x=0

Vậy: S={0}

d) Ta có: $\dfrac{x+1}{100}+\dfrac{x+2}{99}=\dfrac{x+3}{98}+\dfrac{x+4}{97}$

$\Leftrightarrow\dfrac{x+1}{100}+1+\dfrac{x+2}{99}+1=\dfrac{x+3}{98}+1+\dfrac{x+4}{97}+1$

$\Leftrightarrow\dfrac{x+101}{100}+\dfrac{x+101}{99}=\dfrac{x+101}{98}+\dfrac{x+101}{97}$

$\Leftrightarrow\dfrac{x+101}{100}+\dfrac{x+101}{99}-\dfrac{x+101}{98}-\dfrac{x+101}{97}=0$

$\Leftrightarrow\left(x+101\right)\left(\dfrac{1}{100}+\dfrac{1}{99}-\dfrac{1}{98}-\dfrac{1}{97}\right)=0$

mà $\dfrac{1}{100}+\dfrac{1}{99}-\dfrac{1}{98}-\dfrac{1}{97}\ne0$

nên x+101=0

hay x=-101

Vậy: S={-101}

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👁💧👄💧👁

23 tháng 1 2021

a) $\dfrac{x-3}{5}=6-\dfrac{1-2x}{3}\\ \Leftrightarrow\dfrac{3\left(x-3\right)}{15}=\dfrac{90-5\left(1-2x\right)}{15}\\ \Leftrightarrow3x-9=90-5+10x\\ \Leftrightarrow3x-10x=90-5+9\\ \Leftrightarrow-7x=94\\ \Leftrightarrow x=\dfrac{-94}{7}$

Vậy $x=\dfrac{-94}{7}$ là nghiệm của pt

b) $\dfrac{3x-2}{6}-5=\dfrac{3-2\left(x+7\right)}{4}\\ \Leftrightarrow\dfrac{2\left(3x-2\right)-60}{12}=\dfrac{9-6\left(x+7\right)}{12}\\ \Leftrightarrow6x-4-60=9-6x-42\\ \Leftrightarrow6x+6x=9-42+4+60\\ \Leftrightarrow12x=31\\ \Leftrightarrow x=\dfrac{31}{12}$

Vậy $x=\dfrac{31}{12}$ là nghiệm của pt

c) $3\left(x-1\right)+3=5x\\ \Leftrightarrow3x+3+3=5x\\ \Leftrightarrow5x-3x=3+3\\ \Leftrightarrow2x=6\\ \Leftrightarrow x=3$

Vậy x = 3 là nghiệm của pt

d) $\dfrac{x+1}{100}+\dfrac{x+2}{99}=\dfrac{x+3}{98}+\dfrac{x+4}{97}\\ \Leftrightarrow\left(\dfrac{x+1}{100}+1\right)+\left(\dfrac{x+2}{99}+1\right)=\left(\dfrac{x+3}{98}+1\right)+\left(\dfrac{x+4}{97}+1\right)\\ \Leftrightarrow\dfrac{x+101}{100}+\dfrac{x+101}{99}-\dfrac{x+101}{98}-\dfrac{x+101}{97}=0\\ \Leftrightarrow\left(x+101\right)\left(\dfrac{1}{100}+\dfrac{1}{99}-\dfrac{1}{98}-\dfrac{1}{97}\right)=0\\ \Leftrightarrow x+101=0\\ \Leftrightarrow x=-101$

Vậy x = -101 là nghiệm của pt

e) $\dfrac{59-x}{41}+\dfrac{57-x}{43}+\dfrac{55-x}{45}+\dfrac{53-x}{47}=-4\\ \Leftrightarrow\left(\dfrac{59-x}{41}+1\right)+\left(\dfrac{57-x}{43}+1\right)+\left(\dfrac{53-x}{45}+1\right)+\left(\dfrac{53-x}{47}+1\right)=0\\ \Leftrightarrow\dfrac{100-x}{41}+\dfrac{100-x}{43}+\dfrac{100-x}{45}+\dfrac{100-x}{47}=0\\ \Leftrightarrow\left(100-x\right)\left(\dfrac{1}{41}+\dfrac{1}{43}+\dfrac{1}{45}+\dfrac{1}{47}\right)=0\\ \Leftrightarrow100-x=0\\ \Leftrightarrow x=100$

Vậy x = 100 là nghiệm của pt

f) $\dfrac{x-90}{10}+\dfrac{x-76}{12}+\dfrac{x-58}{14}+\dfrac{x-36}{16}+\dfrac{x-15}{17}=15\\ \Leftrightarrow\left(\dfrac{x-90}{10}-1\right)+\left(\dfrac{x-76}{12}-2\right)+\left(\dfrac{x-58}{14}-3\right)+\left(\dfrac{x-36}{16}-4\right)+\left(\dfrac{x-15}{17}-5\right)=0\\ \Leftrightarrow\dfrac{x-100}{10}+\dfrac{x-100}{12}+\dfrac{x-100}{14}+\dfrac{x-100}{16}+\dfrac{x-100}{17}=0\\ \Leftrightarrow\left(x-100\right)\left(\dfrac{1}{10}+\dfrac{1}{12}+\dfrac{1}{14}+\dfrac{1}{16}+\dfrac{1}{17}\right)=0\\ \Leftrightarrow x-100=0\\ \Leftrightarrow x=100$

Vậy x = 100 là nghiệm của pt

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

1

NL

Nguyễn Lê Phước Thịnh

29 tháng 10 2021

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

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

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

Đúng(2)

G

ggsufuu

19 tháng 2 2022

giải phương trình

1)$\left(x-2\right)\left(3+2x\right)-2x\left(x+5\right)=6$

2)$x^2-4-\left(x-5\right)\left(x-2\right)=0$

3)$\dfrac{x-3}{3}-\dfrac{x+2}{2}=\dfrac{x}{6}$

4)$\dfrac{x+2}{x-2}-\dfrac{x-2}{x+2}+\dfrac{3x-1}{x-4}-6$

5)$\dfrac{96}{x^2-16}=\dfrac{2x-1}{x+4}+\dfrac{3x-1}{x-4}-6$

#Toán lớp 8

3

MH

Minh Hiếu

19 tháng 2 2022

1) $\left(x-2\right)\left(3+2x\right)-2x\left(x+5\right)=6$

$3x+2x^2-6-4x-2x^2-10x-6=0$

$-11x=12$

$x=-\dfrac{12}{11}$

2) $x^2-4-\left(x-5\right)\left(x-2\right)=0$

$\left(x-2\right)\left(x+2\right)-\left(x-5\right)\left(x-2\right)=0$

$\left(x-2\right)\left(x+2-x+5\right)=0$

$7\left(x-2\right)=0$

$\Leftrightarrow x=2$

Đúng(2)

NH

Nguyễn Huy Tú ( ✎﹏IDΣΛ亗 )

19 tháng 2 2022

1, $3x+2x^2-6-4x-2x^2-10x=0\Leftrightarrow-11x-6=0\Leftrightarrow x=-\dfrac{6}{11}$

2, $\left(x-2\right)\left(x+2\right)-\left(x-5\right)\left(x-2\right)=0$

$\Leftrightarrow\left(x-2\right)\left(x+2-x+5\right)=0\Leftrightarrow x=2$

3, bạn xem lại đề

5, đk x khác -4 ; 4

$96=\left(2x-1\right)\left(x-4\right)+\left(3x-1\right)\left(x+4\right)-6\left(x^2-16\right)$

$\Leftrightarrow96=2x^2-9x+4+3x^2+11x-4-6x^2+96$

$\Leftrightarrow-x^2+2x=0\Leftrightarrow-x\left(x-2\right)=0\Leftrightarrow x=0;x=2$(tm)

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

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

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

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,...

LT

Lê Thị Ngọc Duyên

20 tháng 8 2017

1

TT

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.

LT

Lê Thị Ngọc Duyên

20 tháng 8 2017

Ths bn nhé