$\dfrac{3}{7}$ - $\dfrac{a}{b}$ $\dfrac{2}{3}$ = $\dfrac{1}{2}$

KK

✎﹏Kim Kim✧❤‿✶🌈(*•.¸♡ţęąɱ ƒŗęę ƒįŗę...

4 tháng 8 2023

$\dfrac{3}{7}-\dfrac{a}{b}+\dfrac{2}{3}=\dfrac{1}{2}\\ \dfrac{23}{21}-\dfrac{a}{b}=\dfrac{1}{2}\\ \dfrac{a}{b}=\dfrac{23}{21}-\dfrac{1}{2}\\ \dfrac{a}{b}=\dfrac{25}{42}$

Vậy a=25; b=42

Tính giá trị các biểu thức sau theo cách hợp lí nhất. a) $\mathrm{A}=\left(\dfrac{2}{7} \cdot \dfrac{1}{4}-\dfrac{1}{3} \cdot \dfrac{2}{7}\right):\left(\dfrac{2}{7} \cdot \dfrac{3}{9}-\dfrac{2}{7} \cdot \dfrac{2}{5}\right)$; b) $\mathrm{B}=\dfrac{\left(\dfrac{1}{5}-\dfrac{2}{7}\right) \cdot \dfrac{3}{4}-\dfrac{3}{4} \cdot\left(\dfrac{1}{3}-\dfrac{2}{7}\right)}{\dfrac{1}{5} \cdot \dfrac{2}{7}-\dfrac{1}{3} \cdot\left(\dfrac{2}{7}+\dfrac{3}{9}\right)+\dfrac{3}{9} \cdot \dfrac{1}{5}}...

TD

Thầy Đức Anh

Giáo viên VIP

27 tháng 4 2022

#Toán lớp 7

12

PT

Phạm Trường Giang

VIP

22 tháng 6 2022

a) $A = [\frac{2}{7} (\frac{1}{4} - \frac{1}{3})] : [\frac{2}{7} (\frac{1}{3} - \frac{2}{5})] = (\frac{1}{4} - \frac{1}{3}) : (\frac{1}{3} - \frac{2}{5}) = 1 \frac{1}{4}$ .
b) $B = \frac{\frac{3}{4} (\frac{1}{5} - \frac{2}{7} - \frac{1}{3} + \frac{2}{7})}{\frac{1}{5} (\frac{2}{7} + \frac{1}{3}) - \frac{1}{3} (\frac{2}{7} + \frac{1}{3})} = \frac{\frac{3}{4} (\frac{1}{5} - \frac{1}{3})}{(\frac{1}{5} - \frac{1}{3}) (\frac{2}{7} + \frac{1}{3})} = 1 \frac{11}{52}$ .

T

TINH

13 tháng 7 2022

a) $\mathrm{A}=\left[\dfrac{2}{7}\left(\dfrac{1}{4}-\dfrac{1}{3}\right)\right]:\left[\dfrac{2}{7}\left(\dfrac{1}{3}-\dfrac{2}{5}\right)\right]=\left(\dfrac{1}{4}-\dfrac{1}{3}\right):\left(\dfrac{1}{3}-\dfrac{2}{5}\right)=1 \dfrac{1}{4}$ .
b) $\mathrm{B}=\dfrac{\dfrac{3}{4}\left(\dfrac{1}{5}-\dfrac{2}{7}-\dfrac{1}{3}+\dfrac{2}{7}\right)}{\dfrac{1}{5}\left(\dfrac{2}{7}+\dfrac{1}{3}\right)-\dfrac{1}{3}\left(\dfrac{2}{7}+\dfrac{1}{3}\right)}=\dfrac{\dfrac{3}{4}\left(\dfrac{1}{5}-\dfrac{1}{3}\right)}{\left(\dfrac{1}{5}-\dfrac{1}{3}\right)\left(\dfrac{2}{7}+\dfrac{1}{3}\right)}=1 \dfrac{11}{52}$

NT

Nguyet Tran

9 tháng 5 2022

a.$\dfrac{2}{7}$ x $\dfrac{4}{3}$ + $\dfrac{2}{6}$

B.$\dfrac{4}{7}$ : 2 + $\dfrac{4}{7}$

C.$\dfrac{1}{3}+\dfrac{3}{4}-\dfrac{1}{5}:\dfrac{2}{3}$

#Toán lớp 4

3

NN

Nguyễn Ngọc Khánh Huyền

9 tháng 5 2022

a) ^{_{$\dfrac{2}{7}\times\dfrac{4}{3}+\dfrac{2}{6}$}}

^{_{$=\dfrac{8}{21}+\dfrac{2}{6}$}}

^{_{$=\dfrac{5}{7}$}}

b) ^{_{$\dfrac{4}{7}:2+\dfrac{4}{7}$}}

^{_{$=\dfrac{2}{7}+\dfrac{4}{7}$}}

^{_{$=\dfrac{6}{7}$}}

c) ^{_{$\dfrac{1}{3}+\dfrac{3}{4}-\dfrac{1}{5}:\dfrac{2}{3}$}}

^{_{$=\dfrac{13}{12}-\dfrac{3}{10}$}}

^{_{$=\dfrac{47}{60}$}}

ID

I don't Know

9 tháng 5 2022

a $\dfrac{8}{21}+\dfrac{2}{6}=\dfrac{16}{42}+\dfrac{14}{42}=\dfrac{30}{42}=\dfrac{5}{7}$

$b$ $\dfrac{4}{7}\times\dfrac{1}{2}+\dfrac{4}{7}=\dfrac{2}{7}+\dfrac{4}{7}=\dfrac{6}{7}$

$c$ $\dfrac{1}{3}+\dfrac{3}{4}-\dfrac{1}{5}\times\dfrac{3}{2}=\dfrac{1}{3}+\dfrac{3}{4}-\dfrac{3}{10}=\dfrac{20}{60}+\dfrac{45}{60}-\dfrac{18}{60}=\dfrac{47}{60}$

$\dfrac{3}{5}+\dfrac{a}{b}=5$ $\dfrac{a}{b}-\dfrac{4}{7}=\dfrac{5}{6}$ $\dfrac{2}{3}$ x $\dfrac{a}{b}=\dfrac{3}{5}$$\dfrac{a}{b}:\dfrac{2}{7}=3+\dfrac{2}{3}$ $\dfrac{7}{5}-\dfrac{a}{b}=\dfrac{2}{5}:2$$\dfrac{3}{5}:\dfrac{a}{b}=\dfrac{2}{7}$ ÉT O...

FS

FAN ST - Hiha

6 tháng 5 2022

#Toán lớp 4

3

TC

TV Cuber

6 tháng 5 2022

a)$\dfrac{a}{b}=5-\dfrac{3}{5}=\dfrac{25}{5}-\dfrac{3}{5}=\dfrac{22}{5}$

b)$\dfrac{a}{b}=\dfrac{5}{6}+\dfrac{4}{7}=\dfrac{35}{42}+\dfrac{24}{42}=\dfrac{59}{42}$

c)$\dfrac{a}{b}=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{3}{5}\times\dfrac{3}{2}=\dfrac{9}{10}$

TC

TV Cuber

6 tháng 5 2022

d)$\dfrac{a}{b}=3\times\dfrac{2}{7}=\dfrac{6}{7}$

e)$\dfrac{a}{b}=\dfrac{7}{5}-\left(\dfrac{2}{5}\times\dfrac{1}{2}\right)=\dfrac{7}{5}-\dfrac{1}{5}=\dfrac{6}{5}$

VG

Vũ Gia Linh

9 tháng 7 2023

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

B= ($\dfrac{2}{3}$)³ : ($\dfrac{2}{3}$)² + (-1$\dfrac{1}{2}$) : 150%

3

ND

Nguyễn Đức Trí

VIP

9 tháng 7 2023

$A=12\dfrac{2}{5}.\left(\dfrac{-7}{3}\right)-3\dfrac{2}{5}.\left(\dfrac{-7}{3}\right)$

$A=\dfrac{62}{5}.\left(\dfrac{-7}{3}\right)-\dfrac{17}{5}.\left(\dfrac{-7}{3}\right)$

$A=\left(\dfrac{-7}{3}\right).\left(\dfrac{62}{5}-\dfrac{17}{5}\right)$

$A=\left(\dfrac{-7}{3}\right).\dfrac{45}{5}$

$A=-21$

$B=\left(\dfrac{2}{3}\right)^3:\left(\dfrac{2}{3}\right)^2+\left(-1\dfrac{1}{2}\right):150\%$

$B=\left(\dfrac{2}{3}\right)^1-\dfrac{3}{2}:1,5$

$B=\dfrac{2}{3}-\dfrac{3}{2}:\dfrac{3}{2}$

$B=\dfrac{2}{3}-1$

$B=-\dfrac{1}{3}$

GH

Gia Hân

VIP

9 tháng 7 2023

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

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

A = ($\dfrac{-7}{3}$) . ( $\dfrac{62}{5}$ - $\dfrac{17}{5}$ )

A = ($\dfrac{-7}{3}$) . 9

A = $\dfrac{-7.9}{3}$

A = $\dfrac{-63}{3}$ = -21

TN

Tiên Nữ Bedee

14 tháng 5 2021

a) $\dfrac{2}{5}+\dfrac{4}{3}:\dfrac{-2}{3}$

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

c) $\dfrac{-3}{5}.\dfrac{4}{7}+\dfrac{3}{7}.\dfrac{-3}{5}+\dfrac{3}{5}$

d) 40% $-1\dfrac{5}{7}:\dfrac{3}{7}+\left|\dfrac{-9}{5}\right|$

5

PT

Phong Thần

14 tháng 5 2021

$a.\dfrac{2}{3}+\dfrac{4}{3}:\dfrac{-2}{3}=\dfrac{2}{3}+\left(-2\right)=\dfrac{-4}{3}$

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

$c.\dfrac{-3}{5}.\dfrac{4}{7}+\dfrac{3}{7}.\dfrac{-3}{5}+\dfrac{3}{5}\\ =\dfrac{-3}{5}\left(\dfrac{4}{7}+\dfrac{3}{7}\right)+\dfrac{3}{5}\\ =\dfrac{-3}{5}+\dfrac{3}{5}=0$

MT

Mun Tân Yên

14 tháng 5 2021

a) $\dfrac{2}{5}+\dfrac{4}{3}:\dfrac{-2}{3}$

$=\dfrac{2}{5}+\dfrac{4}{3}.\dfrac{-3}{2}$

$=\dfrac{2}{5}+-2$

$=\dfrac{2}{5}+\dfrac{-10}{5}$

$=\dfrac{-8}{5}$

a)$\dfrac{-3}{7}+\dfrac{15}{26}-\left(\dfrac{2}{13}-\dfrac{3}{7}\right)$b)$2.\dfrac{3}{7}+\left(\dfrac{2}{9}-1\dfrac{3}{7}\right)-\dfrac{5}{3}:\dfrac{1}{9}$c)$\dfrac{-11}{23}.\dfrac{6}{7}+\dfrac{8}{7}.\dfrac{-11}{23}-\dfrac{1}{23}$d)$\left(\dfrac{377}{-231}-\dfrac{123}{89}+\dfrac{34}{791}\right).\left(\dfrac{1}{6}-\dfrac{1}{8}-\dfrac{1}{24}\right)$ nhanh lên giúp mình...

H

huongff2k3

23 tháng 7 2021

2

NL

Nguyễn Lê Phước Thịnh

23 tháng 7 2021

a) Ta có: $\dfrac{-3}{7}+\dfrac{15}{26}-\left(\dfrac{2}{13}-\dfrac{3}{7}\right)$

$=\dfrac{-3}{7}+\dfrac{15}{26}-\dfrac{2}{13}+\dfrac{3}{7}$

$=\dfrac{15}{26}-\dfrac{4}{26}$

$=\dfrac{11}{26}$

b) Ta có: $2\cdot\dfrac{3}{7}+\left(\dfrac{2}{9}-1\dfrac{3}{7}\right)-\dfrac{5}{3}:\dfrac{1}{9}$

$=\dfrac{6}{7}+\dfrac{2}{9}-\dfrac{10}{7}-\dfrac{5}{3}\cdot9$

$=\dfrac{-4}{7}+\dfrac{2}{9}-15$

$=\dfrac{-36}{63}+\dfrac{14}{63}-\dfrac{945}{63}$

$=\dfrac{-967}{63}$

c) Ta có: $\dfrac{-11}{23}\cdot\dfrac{6}{7}+\dfrac{8}{7}\cdot\dfrac{-11}{23}-\dfrac{1}{23}$

$=\dfrac{-11}{23}\cdot\left(\dfrac{6}{7}+\dfrac{8}{7}\right)-\dfrac{1}{23}$

$=\dfrac{-11}{23}\cdot2-\dfrac{1}{23}$

$=-1$

NL

Nguyễn Lê Phước Thịnh

23 tháng 7 2021

d) Ta có: $\left(\dfrac{377}{-231}-\dfrac{123}{89}+\dfrac{34}{791}\right)\cdot\left(\dfrac{1}{6}-\dfrac{1}{8}-\dfrac{1}{24}\right)$

$=\left(\dfrac{-377}{231}-\dfrac{123}{89}+\dfrac{34}{791}\right)\cdot\left(\dfrac{4}{24}-\dfrac{3}{24}-\dfrac{1}{24}\right)$

$=\left(\dfrac{-377}{231}-\dfrac{123}{89}+\dfrac{34}{791}\right)\cdot0$

=0

Tìm x, biết: a) $\dfrac{-2}{5}$ + $\dfrac{4}{5}$ . x = $\dfrac{3}{5}$ b) $\dfrac{-3}{7}$ - $\dfrac{4}{7}$ : x = $\dfrac{2}{5}$ c) $\dfrac{4}{7}$ . x + $\dfrac{2}{3}$ = $\dfrac{-1}{5}$ d) $\dfrac{5}{7}$ : x -1...

LP

Lê Phương Linh

27 tháng 8 2023

3

NT

Nguyễn Thị Thương Hoài

Giáo viên VIP

27 tháng 8 2023

a, - $\dfrac{2}{5}$ + $\dfrac{4}{5}$.$x$ = $\dfrac{3}{5}$

$\dfrac{4}{5}$.$x$ = $\dfrac{3}{5}$+ $\dfrac{2}{5}$

$\dfrac{4}{5}$.$x$ = 1

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

b, - $\dfrac{3}{7}$ - $\dfrac{4}{7}$: $x$ = $\dfrac{2}{5}$

$\dfrac{4}{7}$: $x$ = - $\dfrac{3}{7}$ - $\dfrac{2}{5}$

$\dfrac{4}{7}$: $x$ = - $\dfrac{29}{35}$

$x$ = $\dfrac{4}{7}$: (- $\dfrac{29}{35}$ )

$x$ = - $\dfrac{20}{29}$

NT

Nguyễn Thị Thương Hoài

Giáo viên VIP

27 tháng 8 2023

c, $\dfrac{4}{7}$.$x$ + $\dfrac{2}{3}$ = - $\dfrac{1}{5}$

$\dfrac{4}{7}$.$x$ = -$\dfrac{1}{5}$ - $\dfrac{2}{3}$

$\dfrac{4}{7}$.$x$ = - $\dfrac{13}{15}$

$x$ = - $\dfrac{13}{15}$: $\dfrac{4}{7}$

$x$ = - $\dfrac{91}{60}$

a) $\dfrac{5}{7}$+$\dfrac{3}{4}$.$\dfrac{-11}{2}$b) ($\dfrac{12}{17}$+$\dfrac{19}{7}$) - ($\dfrac{-5}{17}$-$\dfrac{3}{7}$)c)...

PV

Phạm Vũ Hà My

15 tháng 11 2021

#Toán lớp 7

1

NH

Nguyễn Hoàng Minh

15 tháng 11 2021

$a,=\dfrac{5}{7}-\dfrac{33}{8}=-\dfrac{191}{56}\\ b,=\left(\dfrac{12}{17}+\dfrac{5}{17}\right)+\left(\dfrac{19}{7}+\dfrac{3}{7}\right)=1+3=4\\ c,=\left(0,125\cdot8\right)^{12}-\left(\dfrac{45}{15}\right)^3=1-3^3=-26\\ d,=\left(-\dfrac{1}{3}\right)\left(5\dfrac{2}{7}-2\dfrac{2}{7}\right)=-\dfrac{1}{3}\cdot3=-1\\ e,=\dfrac{3^4\cdot3^6}{3^9}=3$

PV

Phạm Vũ Hà My

15 tháng 11 2021

Thank you ^^

tìm x bt a) $\dfrac{2}{3}$x - $\dfrac{7}{6}$ = $\dfrac{12}{7}$ - $\dfrac{1}{2}$ b) ( $1\dfrac{1}{2}$ + $\dfrac{5}{3}$ - $\dfrac{1}{6}$ ) : x...

TG

Trần Gia Hân

10 tháng 3 2023

1

AH

Akai Haruma

Giáo viên

10 tháng 3 2023

Lời giải:

a.

$\frac{2}{3}x-\frac{7}{6}=\frac{12}{7}-\frac{1}{2}=\frac{17}{14}$

$\frac{2}{3}x=\frac{17}{14}+\frac{7}{6}=\frac{50}{21}$

$x=\frac{50}{21}: \frac{2}{3}=\frac{25}{7}$

b.

$(1\frac{1}{2}+\frac{5}{3}-\frac{1}{6}):x=\frac{3}{4}-\frac{1}{2}$

$3:x=\frac{1}{4}$

$x=3: \frac{1}{4}=12$

Bài 1. Tính A= $\left(8\dfrac{2}{7}-4\dfrac{2}{7}\right)-3\dfrac{4}{9}$ B= $\left(10\dfrac{2}{9}-6\dfrac{2}{9}\right)+2\dfrac{3}{5}$Bài 2. Tính a) $5\dfrac{1}{2}.3\dfrac{1}{4}$ b) $6\dfrac{1}{3}:4\dfrac{2}{9}$ ...

MN

Miru nèe

16 tháng 6 2021

3

Y

Yeutoanhoc

16 tháng 6 2021

`A=(8 2/7-4 2/7)-3 4/9`

`=8+2/7-4-2/7-3-4/9`

`=4-3-4/9`

`=1-4/9=5/9`

`B=(10 2/9-6 2/9)+2 3/5`

`=10+2/9-6-2/9+2+3/5`

`=4+2+3/5`

`=6+3/5=33/5`

Bài 2:

`a)5 1/2*3 1/4`

`=11/2*13/4`

`=143/8`

`b)6 1/3:4 2/9`

`=19/3:38/9`

`=19/3*9/38=3/2`

`c)4 3/7*2`

`=31/7*2`

`=62/7`

T

꧁_͏ͥ͏_͏ͣ͏_͏ͫ͏ ¡亗ᵛᶰシ๖ۣۜT๖ۣۜR๖ۣۜÂ๖ۣ...

16 tháng 6 2021

Bài 1:

$A=\left(8\dfrac{2}{7}-4\dfrac{2}{7}\right)-3\dfrac{4}{9}$

$A=\left(\dfrac{58}{7}-\dfrac{30}{7}\right)-\dfrac{31}{9}$

$A=4-\dfrac{31}{9}$

$A=\dfrac{5}{9}$

$B=\left(10\dfrac{2}{9}-6\dfrac{2}{9}\right)+2\dfrac{3}{5}$

$B=\left(\dfrac{92}{9}-\dfrac{56}{9}\right)+\dfrac{13}{5}$

$B=4+\dfrac{13}{5}$

$B=\dfrac{33}{5}$