Bài 1: tính: a) 8 và 5/9 : 5 và 1/2 b) 7 và 3/4 - 2 và 1/8 c) 1 và 3/4 x 2 và 5/6 d) 7 - 2 và 2/3 e) 2 và 3/7 x 1 và 3/4 g) 5 và 1/3 : 3 và 1/5 Bài 2: tìm X: X : 3 và 1/3= 2 và 2/5 + 7/10 Và là biểu thị cho hỗn số nhé

Bài 1:

a, 85995​:51221​

= 779977​: 112211​

= 779977​ x 211112​

= 149914​
 

b, 73443​ - 21881​

= 314431​ - 178817​

= 458845​

c, 13443​ x 25665​

= 7447​ x 176617​

= 1192424119​
 

d, 7 - 22332​

= 213321​ - 8338​

= 133313​
 

e, 23773​ x 13443​

= 177717​ x 7447​

= 174417​
 

g, 51331​: 31551​

= 163316​ : 165516​

= 5335​
 

Bài 2: 

$x$: 31331​ = 25775​ + 710107​

$x$ : 103310​ = 197719​ + 710107​

$x$ : 103310​ = 2397070239​

$x$         = 2397070239​ x 103310​

$x$         = 2392121239​
 

a: \(12\dfrac{1}{3}-\left(3\dfrac{3}{4}+4\dfrac{3}{4}\right)\)

\(=\dfrac{37}{3}-3-4-\dfrac{3}{2}\)

\(=\dfrac{74-9}{6}-7=\dfrac{65}{6}-7=\dfrac{65-42}{7}=\dfrac{23}{7}\)

b: \(3\dfrac{5}{6}+2\dfrac{1}{6}\cdot6\)

\(=3+\dfrac{5}{6}+\dfrac{13}{6}\cdot6\)

\(=16+\dfrac{5}{6}=\dfrac{101}{6}\)

c: \(3\dfrac{1}{2}+4\dfrac{5}{7}-5\dfrac{5}{14}\)

\(=3+\dfrac{1}{2}+4+\dfrac{5}{7}-5-\dfrac{5}{14}\)

\(=2+\dfrac{7+10-5}{14}=2+\dfrac{12}{14}=2+\dfrac{6}{7}=\dfrac{20}{7}\)

d: \(=\dfrac{9}{2}+\dfrac{1}{2}:\dfrac{11}{2}=\dfrac{9}{2}+\dfrac{1}{11}=\dfrac{99+2}{22}=\dfrac{101}{22}\)

các bn giải mk nha

 \(a,11\dfrac{3}{4}-\left(6\dfrac{5}{6}-4\dfrac{1}{2}\right)+1\dfrac{2}{3}\)

\(=\dfrac{47}{4}-\left(\dfrac{41}{6}-\dfrac{9}{2}\right)+\dfrac{5}{3}\)
\(=\dfrac{47}{4}-\left(\dfrac{41}{6}-\dfrac{27}{6}\right)+\dfrac{5}{3}\)

\(=\dfrac{47}{4}-\dfrac{14}{6}+\dfrac{5}{3}\)

\(=\dfrac{47}{4}-\dfrac{7}{3}+\dfrac{5}{3}\)

\(=\dfrac{47}{4}-\left(\dfrac{7}{3}+\dfrac{5}{3}\right)\)

\(=\dfrac{47}{4}-\dfrac{12}{3}\)

\(=\dfrac{47}{4}-4\)

\(=\dfrac{47}{4}-\dfrac{16}{4}\)

\(=\dfrac{31}{4}\)

c) Ta có: \(4\dfrac{3}{7}:\left(\dfrac{7}{5}\cdot4\dfrac{3}{7}\right)\)

\(=\dfrac{31}{7}:\left(\dfrac{7}{5}\cdot\dfrac{31}{7}\right)\)

\(=\dfrac{31}{7}:\dfrac{31}{5}\)

\(=\dfrac{5}{7}\)

a, \(\Leftrightarrow2x^2=72\)

\(\Leftrightarrow x^2=36\)

\(\Leftrightarrow x=\pm6\)

Vậy ...

\(b,\Leftrightarrow\dfrac{3}{5}x-0,75=2\dfrac{4}{5}.\dfrac{3}{7}=\dfrac{6}{5}\)

\(\Leftrightarrow\dfrac{3}{5}x=\dfrac{6}{5}+0,75=\dfrac{39}{20}\)

\(\Leftrightarrow x=\dfrac{39}{20}:\dfrac{3}{5}=\dfrac{13}{4}\)

Vậy ...

\(c,\Leftrightarrow2x=1\dfrac{5}{6}.\dfrac{6}{11}-\dfrac{3}{10}=\dfrac{7}{10}\)

\(\Leftrightarrow x=\dfrac{7}{10}:2=\dfrac{7}{20}\)

Vậy ...

\(d,\Leftrightarrow\dfrac{1}{x-7\dfrac{1}{3}}=1.5:2\dfrac{1}{4}=\dfrac{2}{3}\)

\(\Leftrightarrow x-7\dfrac{1}{3}=\dfrac{3}{2}\)

\(\Leftrightarrow x=\dfrac{3}{2}+7\dfrac{1}{3}=\dfrac{53}{6}\)

Vậy ...

a) 2x² - 72 = 0

\(\Rightarrow\) 2x² = 72

\(\Rightarrow\) x² = 36 = 6² = (- 6)²

\(\Rightarrow\) x = 6 hoặc x = - 6

Vậy x = 6 hoặc x = - 6

b) (\(\dfrac{3}{5}\)x - 0,75) : \(\dfrac{3}{7}\) = \(2\dfrac{4}{5}\)

\(\Rightarrow\)  (\(\dfrac{3}{5}\)x - 0,75) : \(\dfrac{3}{7}\) = \(\dfrac{14}{5}\)

\(\Rightarrow\)  \(\dfrac{3}{5}\)x - \(\dfrac{3}{4}\) = \(\dfrac{6}{5}\)

\(\Rightarrow\) \(\dfrac{3}{5}\)x = \(\dfrac{39}{20}\)

\(\Rightarrow\) x = \(\dfrac{13}{4}\)

Vậy x = \(\dfrac{13}{4}\)

c) \(2x+\dfrac{3}{10}=1\dfrac{5}{6}.\dfrac{6}{11}\)

\(\Rightarrow\) \(2x+\dfrac{3}{10}=\dfrac{11}{6}.\dfrac{6}{11}=1\)

\(\Rightarrow\) \(2x=\dfrac{7}{10}\)

\(\Rightarrow\) \(x=\dfrac{7}{20}\)

Vậy \(x=\dfrac{7}{20}\)

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

\(\Rightarrow\) \(\dfrac{9}{4}:\left(x-\dfrac{22}{3}\right)=\dfrac{3}{2}\)

\(\Rightarrow\) \(x-\dfrac{22}{3}=\dfrac{3}{2}\)

\(\Rightarrow\) \(x=\dfrac{53}{6}\)

Vậy \(x=\dfrac{53}{6}\)

\(a)\)\(6\frac{4}{5}-\left(1\frac{2}{3}+3\frac{4}{5}\right)\)

\(=6\frac{4}{5}-1\frac{2}{3}-3\frac{4}{5}\)

\(=\left(6\frac{4}{5}-3\frac{4}{5}\right)-1\frac{2}{3}\)

\(=\left(6+\frac{4}{5}-3-\frac{4}{5}\right)-\frac{5}{3}\)

\(=3-\frac{5}{3}\)

\(=\frac{9}{3}-\frac{5}{3}\)

\(=\frac{4}{3}\)

\(b)\)\(6\frac{5}{7}-(1\frac{3}{4}+2\frac{5}{7})\)

\(=6\frac{5}{7}-1\frac{3}{4}-2\frac{5}{7}\)

\(=\left(6\frac{5}{7}-2\frac{5}{7}\right)-1\frac{3}{4}\)

\(=\left(6+\frac{5}{7}-2-\frac{5}{7}\right)-\frac{7}{4}\)

\(=4-\frac{7}{4}\)

\(=\frac{16}{4}-\frac{7}{4}\)

\(=\frac{9}{4}\)

\(c)\)\(7\frac{5}{9}-\left(2\frac{3}{4}+3\frac{5}{9}\right)\)

\(=7\frac{5}{9}-2\frac{3}{4}-3\frac{5}{9}\)

\(=\left(7\frac{5}{9}-3\frac{5}{9}\right)-2\frac{3}{4}\)

\(=\left(7+\frac{5}{9}-3-\frac{5}{9}\right)-\frac{11}{4}\)

\(=4-\frac{11}{4}\)

\(=\frac{16}{4}-\frac{11}{4}\)

\(=\frac{5}{4}\)

P/s: Câu b bạn thiếu ngoặc.

Linz

 a) 6 và 4/5 - ( 1 và 2/3 + 3 và 4/5)

= 34/5- ( 5/3 + 19/5 )

= 34/5 - 5/3 - 19/5

= (34/5 - 9/5 ) - 5/3

=25/5 -5/3

= 5/1 - 5/3

= 15/3 - 5/3

=10/3

b) 6 và 5/7 - (1 và 3/4 + 2 và 5/7)

=47/7 - (7/4 + 19/7 )

= 47/7 -7/4 - 19/7

= (47/7 -19/7 ) - 7/4

= 28/7 -7/4

=4/1 - 7/4

= 16/4 - 7/4

= 9/4

c) 7 và 5/9 - ( 2 và 3/4 + 3 và 5/9 )

= 68/9 - ( 11/4 + 32/9 )

= 68/9 - 11/4 - 32/9

= (68/9 - 32/9 )- 11/4

= 36/9 -11/4

= 4/1 - 11/4

= 16/4 - 11/4

= 5/4

    Chúc bạn học tốt nha!!!!!

a) 2/3 x + 1/2 = 1/10

2/3 x = 1/10 - 1/2

2/3 x = -2/5

x = -2/5 : 2/3

x = -3/5

b) 2/3 x + 1/5 = 7/10

2/3 x = 7/10 - 1/5

2/3 x = 1/2

x = 1/2 : 2/3

x = 3/4

c) (3 4/5 - 2x) . 1 1/3 = 5

19/5 - 2x = 5 : 4/3

19/5 - 2x = 15/4

2x = 19/5 - 15/4

2x = 1/20

x = 1/20 : 2

x = 1/40

d) x/7 = 6/(-21)

x = 6.7/(-21)

x = -2