Bài 1

a) 3 2/5 - 1/2

= 17/5 - 1/2

= 34/10 - 5/10

= 29/10

b) 4/5 + 1/5 × 3/4

= 4/5 + 3/20

= 16/20 + 3/20

= 19/20

c) 3 1/2 × 1 1/7

= 7/2 × 8/7

= 4

d) 4 1/6 : 2 1/3

= 25/6 : 7/3

= 25/14

Bài 2

a) 3 × 1/2 + 1/4 × 1/3

= 3/2 + 1/12

= 18/12 + 1/12

= 19/12

b) 1 4/5 - 2/3 : 2 1/3

= 9/5 - 2/3 : 7/3

= 9/5 - 2/7

= 63/35 - 10/35

= 53/35

Bài 1

a) 3 2/5 - 1/2

= 17/5 - 1/2

= 34/10 - 5/10

= 29/10

b) 4/5 + 1/5 × 3/4

= 4/5 + 3/20

= 16/20 + 3/20

= 19/20

c) 3 1/2 × 1 1/7

= 7/2 × 8/7

= 4

d) 4 1/6 : 2 1/3

= 25/6 : 7/3

= 25/14

bủh

=1,4 x\(\dfrac{15}{49}-\) \(\left(\dfrac{4}{5}+\dfrac{2}{3}\right)\) : 2\(\dfrac{1}{5}\)

=  \(\dfrac{3}{7}\) - \(\dfrac{22}{15}\) : \(\dfrac{11}{5}\)

= \(\dfrac{3}{7}\) -  \(\dfrac{2}{3}\)

= \(-\dfrac{5}{21}\) 

( 2\(\dfrac{1}{5}\) + \(\dfrac{3}{5}\) \(\times\) \(x\)) = \(\dfrac{3}{4}\)

  \(\dfrac{11}{5}\) + \(\dfrac{3}{5}\)\(x\) = \(\dfrac{3}{4}\)

            \(\dfrac{3}{5}\)\(x\) = \(\dfrac{3}{4}\) - \(\dfrac{11}{5}\)

           \(\dfrac{3}{5}\)\(x\) = - \(\dfrac{29}{20}\)

             \(x\) = -\(\dfrac{29}{12}\)

3\(\dfrac{1}{3}\) x \(x+16\)\(\dfrac{3}{4}\)= 13,25

\(\dfrac{10}{3}\) x \(x\) + \(\dfrac{67}{4}\) = 13,25

\(\dfrac{10}{3}\) x \(x\) = 13,25 - \(\dfrac{67}{4}\)

\(\dfrac{10}{3}\times x=\) \(\dfrac{103}{28}\) 

          \(x\) = \(\dfrac{103}{28}:\dfrac{10}{3}\)

          \(x=\) \(\dfrac{309}{280}\)

\(a,4\dfrac{1}{4}-2=\dfrac{17}{4}-2=\dfrac{9}{4};\dfrac{5}{8}+2\dfrac{3}{5}=\dfrac{5}{8}+\dfrac{13}{5}=\dfrac{129}{40}\\ b,4\dfrac{4}{9}:2=\dfrac{40}{9}\cdot\dfrac{1}{2}=\dfrac{20}{9};\dfrac{2}{3}+3\dfrac{1}{6}=\dfrac{2}{3}+\dfrac{19}{6}=\dfrac{23}{6}\\ c,3\dfrac{1}{5}+2=\dfrac{9}{5}+2=\dfrac{19}{5};\dfrac{3}{5}-2\dfrac{4}{5}=\dfrac{3}{5}-\dfrac{14}{5}=-\dfrac{11}{5}\)

\(d,5\dfrac{1}{7}-2=\dfrac{36}{7}-2=\dfrac{22}{7};\dfrac{4}{5}:1\dfrac{1}{5}=\dfrac{4}{5}:\dfrac{6}{5}=\dfrac{2}{3}\\ e,2\dfrac{3}{5}+1=\dfrac{13}{5}+1=\dfrac{18}{5};\dfrac{1}{4}\cdot2\dfrac{2}{3}=\dfrac{1}{4}\cdot\dfrac{8}{3}=\dfrac{2}{3}\\ f,4\dfrac{1}{3}\cdot1=\dfrac{13}{3};\dfrac{1}{2}+5\dfrac{2}{7}=\dfrac{1}{2}+\dfrac{37}{7}=\dfrac{81}{14}\)

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)\(1\dfrac{3}{4}x-5=3\dfrac{1}{3}\text{⇔}\dfrac{7}{4}x-5=\dfrac{10}{3}\text{⇔}\dfrac{7}{4}x=\dfrac{25}{3}\text{⇔}x=\dfrac{100}{21}\)

b)\(\dfrac{2}{3}x+\dfrac{1}{4}=\dfrac{7}{12}\text{⇔}\dfrac{2}{3}x=\dfrac{1}{3}\text{⇔}x=\dfrac{1}{2}\)

c)\(\dfrac{1}{3}+\dfrac{2}{5}\left(x+1\right)=1\text{⇔}\dfrac{2}{5}\left(x+1\right)=\dfrac{2}{3}\text{⇔}x+1=\dfrac{5}{3}\text{⇔}x=\dfrac{2}{3}\)

d)\(\dfrac{1}{4}+\dfrac{1}{3}:3x=-5\text{⇔}\dfrac{1}{3}:3x=-\dfrac{21}{4}\text{⇔}\dfrac{1}{9x}=-\dfrac{21}{4}\text{⇔}9x=-\dfrac{4}{21}\text{⇔}x=-\dfrac{4}{189}\)

a, \(1\dfrac{3}{4}x-5=3\dfrac{1}{3}\)

\(\Rightarrow\dfrac{7}{4}x=5+\dfrac{10}{3}=\dfrac{25}{3}\)

\(\Rightarrow x=\dfrac{25}{3}:\dfrac{7}{4}=\dfrac{100}{21}\)

Vậy ...

b, \(PT\Leftrightarrow\dfrac{2}{3}x=\dfrac{7}{12}-\dfrac{1}{4}=\dfrac{1}{3}\)

\(\Rightarrow x=\dfrac{1}{3}:\dfrac{2}{3}=\dfrac{1}{2}\)

Vậy ....

c, \(PT\Leftrightarrow\dfrac{2}{5}\left(x+1\right)=1-\dfrac{1}{3}=\dfrac{2}{3}\)

\(\Rightarrow x+1=\dfrac{2}{3}:\dfrac{2}{5}=\dfrac{5}{3}\)

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

Vậy ...

d, \(PT\Leftrightarrow\dfrac{1}{3}:3x=-5-\dfrac{1}{4}=\dfrac{1}{9}x=-\dfrac{21}{4}\)

\(\Rightarrow x=-\dfrac{189}{4}\)

Vậy ...

a: \(\Leftrightarrow\left|x\cdot\dfrac{7}{3}-\dfrac{3}{4}\right|=1+\dfrac{1}{3}+\dfrac{2}{3}=2\)

\(\Leftrightarrow\left[{}\begin{matrix}x\cdot\dfrac{7}{3}-\dfrac{3}{4}=2\\x\cdot\dfrac{7}{3}-\dfrac{3}{4}=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{33}{28}\\x=-\dfrac{15}{28}\end{matrix}\right.\)

b: \(\Leftrightarrow\left|x\cdot\dfrac{2}{3}-\dfrac{1}{3}\right|=\dfrac{6}{5}\)

\(\Leftrightarrow\left[{}\begin{matrix}x\cdot\dfrac{2}{3}-\dfrac{1}{3}=-\dfrac{6}{5}\\x\cdot\dfrac{2}{3}-\dfrac{1}{3}=\dfrac{6}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-13}{10}\\x=\dfrac{23}{10}\end{matrix}\right.\)

a) \(3\dfrac{1}{2}-1\dfrac{1}{4}\times1\dfrac{5}{6}\)

\(=\dfrac{7}{2}-\dfrac{5}{4}\times\dfrac{11}{6}\)

\(=\dfrac{7}{2}-\dfrac{55}{24}\)

\(=\dfrac{84}{24}-\dfrac{55}{24}\)

\(=\dfrac{29}{24}\)

b) \(2\dfrac{5}{6}+1\dfrac{2}{3}\div3\dfrac{3}{4}\)

\(=\dfrac{17}{6}+\dfrac{5}{3}\div\dfrac{15}{4}\)

\(=\dfrac{17}{6}+\dfrac{5}{3}\times\dfrac{4}{15}\)

\(=\dfrac{17}{6}+\dfrac{4}{9}\)

\(=\dfrac{153}{54}+\dfrac{24}{54}\)

\(=\dfrac{59}{18}\)

a) 312−114×156321​−141​×165​

=72−54×116=27​−45​×611​

=72−5524=27​−2455​

=8424−5524=2484​−2455​

=2924=2429​
 

b) 256+123÷334265​+132​÷343​

=176+53÷154=617​+35​÷415​

=176+53×415=617​+35​×154​

=176+49=617​+94​

=15354+2454=54153​+5424​

=5918=1859​
 

1:2/5x1/2

=5/2x1/2

=5/4

1/3x2/3-1/4

=2/9-1/4

=-1/36

1/2/3+2/4/5

=5/3+14/5         

=67/15

3/1/2x1/4/5

=7/2x9/5

=63/10

1/4/7-2/3

=11/7-2/3

=19/21

vd câu 1:
ta có x-y=4 =>x=4+y
ta có pt:
4+y/y-2=3/2
=>8+2y=3y-6
=>-y=-14
=>y=14
=>x=4+y=4+14=18
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