6, \(x=\dfrac{9}{2}+\dfrac{1}{2}=\dfrac{10}{2}=5\)

7, \(x=-\dfrac{3}{4}-\dfrac{5}{4}=-\dfrac{8}{4}=-2\)

8, \(x=\dfrac{5}{7}-\dfrac{2}{7}=\dfrac{3}{7}\)

9, \(x=\dfrac{1}{3}+\dfrac{4}{3}=\dfrac{5}{3}\)

10, \(x=-\dfrac{7}{2}-\dfrac{5}{2}=-\dfrac{12}{2}=-6\)

\(6,x-\dfrac{1}{2}=\dfrac{9}{2}\Leftrightarrow x=5\)

\(7,x+\dfrac{5}{4}=\dfrac{-3}{4}\Leftrightarrow x=-2\)

\(8,x+\dfrac{2}{7}=\dfrac{5}{7}\Leftrightarrow x=\dfrac{3}{7}\)

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

\(10,x+\dfrac{5}{2}=\dfrac{-7}{2}\Leftrightarrow x=-6\)

\(x-\dfrac{1}{2}=\dfrac{9}{2}\)

\(x\)        \(=\dfrac{9}{2}+\dfrac{1}{2}=\dfrac{10}{2}=5\)

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

\(x\)        \(=\dfrac{-3}{4}+\dfrac{-5}{4}=\dfrac{-8}{4}=-2\)

\(x+\dfrac{2}{7}=\dfrac{5}{7}\)

\(x\)        \(=\dfrac{5}{7}+\dfrac{-2}{7}=\dfrac{3}{7}\)

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

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

\(x+\dfrac{5}{2}=\dfrac{-7}{2}\)

\(x\)        \(=\dfrac{-7}{2}+\dfrac{-5}{2}=\dfrac{-12}{2}=-6\)

a)  >

b) > 

c) >   

d) < 

1) (x - 35) - 120 = 0

x - 35 = 120

x = 120 + 35

x = 155

2) 310 - (118 - x) = 217

118 - x = 310 - 217

118 - x = 93

x = 118 - 93

x = 25

3) 156 - (x + 61) = 82

x + 61 = 156 - 82

x + 61 = 74

x = 74 - 61

x = 13

4) 814 - (x - 305) = 712

x - 305 = 814 - 712

x - 305 = 102

x = 102 + 305 = 407

5) 100 - 7 - (x - 5) = 58

x - 5 = 93 - 58

x - 5 = 35

x = 35 + 5 = 40

6) 12(x - 1) : 3 = 4³ + 2³

4(x - 1) = 72

x - 1 = 18

x = 18 + 1 = 19

7) 24 + 5x = 7⁵ : 7³

24 + 5x = 49

5x = 25

x = 25 : 5 = 5

8) 5(x - 1) : 3 = 4³ + 2³

\(\dfrac{5}{3}\left(x-1\right)=72\)

x - 1 = \(\dfrac{216}{5}\)

x = 221/5

9) 5(x - 4)² - 7 = 13

5(x - 4)² = 20

(x - 4)² = 4

\(\Rightarrow\left[{}\begin{matrix}x-4=2\\x-4=-2\end{matrix}\right.\)   \(\Rightarrow\left[{}\begin{matrix}x=6\\x=2\end{matrix}\right.\)

10) (x + 1) + (x + 2) + ... + (x + 30) = 795

=> (x + x + x + ... + x) + (1 + 2 + 3 +...+ 30) = 795 (1)

Đặt A = 1 + 2 + 3 +...+ 30

Số số hạng trong A là: (30 - 1) : 1 + 1 = 30 (số)

Tổng A bằng : (30 + 1).30 : 2 =465

Thay A = 465 vào (1) , ta được:

30x + 465 = 795

=> 30x =330

=> x =11

1: =>x-35=120

=>x=120+35=155

2: =>118-x=310-217=93

=>x=118-93=25

3: =>x+61=156-82=74

=>x=74-61=13

4: =>x-305=814-712=102

=>x=102+305=407

5: =>93-(x-5)=58

=>x-5=35

=>x=40

6: =>4(x-1)=64+8=72

=>x-1=18

=>x=19

7: =>5x+24=49

=>5x=25

=>x=5

8: =>5(x-1):3=4^3+2^3=64+8=72

=>5(x-1)=216

=>x-1=216/5

=>x=221/5

 58/7 - (31/9 + 30/7)                  
= 58/7 - 31/9 - 30/7
= (58/7 - 30/7) - 31/9
= 28/7- 31/9
= 4 - 31/9 = 36/9 - 31/9
= 5/9

478/19÷(-5/4)-668/19÷(-5/4)
=(478/19-668/19):(-5/4)
=-10 . (-4/5)
=8

1) Ta có: \(\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{7}{25}\cdot\dfrac{5}{7}\right)\)

\(=\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{1}{5}\right)\)

=0

2) Ta có: \(\dfrac{8}{17}\cdot\dfrac{4}{15}+\dfrac{8}{17}\cdot\dfrac{22}{15}-\dfrac{8}{15}\cdot\dfrac{9}{17}\)

\(=\dfrac{8}{17}\left(\dfrac{4}{15}+\dfrac{22}{15}-\dfrac{9}{15}\right)\)

\(=\dfrac{8}{17}\cdot\dfrac{15}{15}=\dfrac{8}{17}\)

3) Ta có: \(\dfrac{2021}{2}\cdot\dfrac{1}{3}+\dfrac{4042}{4}\cdot\dfrac{1}{5}+\dfrac{6063}{3}\cdot\dfrac{22}{15}\)

\(=\dfrac{2021}{2}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)+2021\cdot\dfrac{22}{15}\)

\(=\dfrac{2021}{2}\cdot\dfrac{8}{15}+\dfrac{2021}{2}\cdot\dfrac{44}{15}\)

\(=\dfrac{2021}{2}\cdot\dfrac{52}{15}\)

\(=\dfrac{52546}{15}\)

4) Ta có: \(\dfrac{4}{7}\cdot\dfrac{2}{13}+\dfrac{8}{13}:\dfrac{7}{4}+\dfrac{4}{7}:\dfrac{13}{2}+\dfrac{4}{7}\cdot\dfrac{1}{13}\)

\(=\dfrac{4}{7}\left(\dfrac{2}{13}+\dfrac{8}{13}+\dfrac{2}{13}+\dfrac{1}{13}\right)\)

\(=\dfrac{4}{7}\)

1) Tính biểu thức:

`1/2+3/4-5/6=6/12+9/12-10/12=5/12`

`(5/6+3/8)xx2/7=(20/24+9/24)xx2/7=29/24xx2/7=29/84`

`(7/6-3/4):3/5=(14/12-9/12)xx5/3=5/12xx5/3=25/36`

`6/7xx2/3:5/7=6/7xx2/3xx7/5=4/5`

` 1/2 + 3/4 - 5/6 = 6/12 + 9/12 - 10/12 = 5/12`

` ( 5/6 + 3/8) xx 2/7 =  ( 20/24 + 9/24) xx 2/7 = 29/24 xx 2/7 = 29/84`

` ( 7/6 - 3/4) : 3/5 = ( 14/12 - 9/12) : 3/5 = 5/12 : 3/5 = 5/12 xx 5/3 = 25/36`

` 6/7 xx 2/3 : 5/7 = 6/7 xx 2/3 xx 7/5  = 4/5`

` 1/2 + 3/4 - 5/6 = 6/12 + 9/12 - 10/12 = 5/12`

` ( 5/6 + 3/8) xx 2/7 =  ( 15/24 + 9/24) xx 2/7 = 29/24 xx 2/7 = 29/84`

` ( 7/6 - 3/4) : 3/5 = ( 14/12 - 9/12) : 3/5 = 5/12 : 3/5 = 5/12 xx 5/3 = 25/36`

` 6/7 xx 2/3 : 5/7 = 6/7 xx 2/3 xx 7/5  = 4/5`