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

Bạn chia từng bài ra được chứ?

a)

`x+1/4xx1/5=4/5`

`x+1/20=4/5`

`x=4/5-1/20`

`x=16/20-1/20`

`x=15/20=3/4`

b)

`3 2/3:x=2 2/3-1 1/2`

`11/3:x=8/3-3/2`

`11/3:x=16/6-9/6`

`11/3:x=7/6`

`x=11/3:7/6`

`x=11/3xx6/7`

`x=22/7`

\(a,x+\dfrac{1}{4}.\dfrac{1}{5}=\dfrac{4}{5}\)

\(\Rightarrow\)\(x+\dfrac{1}{20}=\dfrac{4}{5}\)

\(\Rightarrow x=\dfrac{4}{5}-\dfrac{1}{20}=\dfrac{16}{20}-\dfrac{1}{20}=\dfrac{3}{4}\)

\(b,3\dfrac{2}{3}:x=2\dfrac{2}{3}-1\dfrac{1}{2}\)

\(\Rightarrow\dfrac{11}{3}:x=\dfrac{7}{6}\)

\(\Rightarrow x=\dfrac{11}{3}:\dfrac{7}{6}=\dfrac{22}{7}\)

\(a,x+\dfrac{1}{4}\times\dfrac{1}{5}=\dfrac{4}{5}\)

\(x+\dfrac{1}{20}=\dfrac{4}{5}\)

\(x=\dfrac{4}{5}-\dfrac{1}{20}\)

\(x=\dfrac{16}{20}-\dfrac{1}{20}\)

\(x=\dfrac{15}{20}=\dfrac{3}{4}\)

\(b,3\dfrac{2}{3}:x=2\dfrac{2}{3}-1\dfrac{1}{2}\)

\(\dfrac{11}{3}:x=\dfrac{8}{3}-\dfrac{3}{2}\)

\(\dfrac{11}{3}:x=\dfrac{7}{6}\)

\(x=\dfrac{11}{3}:\dfrac{7}{6}=\dfrac{22}{7}\)

a: =>x+1/20=4/5

=>x=4/5-1/20=16/20-1/20=15/20=3/4

b: =>11/3:x=8/3-3/2=16/6-9/6=7/6

=>x=11/3:7/6=11/3*6/7=66/21=22/7

a) x - 3/2 = 4/3 

    x = 4/3 + 3/2

    x = 8/6 + 9/6 = 17/6

b) 2/5 * x = 1/3

    x = 1/3 : 2/5

    x = 1/3 x 5/2 = 5/6

c) x - 4/9 = 3/7 : 9/14

    x - 4/9 = 2/3

    x = 2/3 + 4/9

    x = 6/9 + 4/9 = 10/9

d) 3/5 * x - 1/2 = 1/5

    3/5 * x = 1/5 + 1/2 = 7/10

    x = 7/10 : 3/5

    x = 7/10 * 5/3 = 7/6

a/\(x-\dfrac{3}{2}=\dfrac{4}{3}\)
\(x=\dfrac{4}{3}+\dfrac{3}{2}\)
\(x=\dfrac{17}{6}\)
b/\(\dfrac{2}{5}\times x=\dfrac{1}{3}\)
\(x=\dfrac{1}{3}:\dfrac{2}{5}\)
\(x=\dfrac{5}{6}\)
c/\(x-\dfrac{4}{9}=\dfrac{3}{7}:\dfrac{9}{14}\)
\(x-\dfrac{4}{9}=\dfrac{2}{3}\)
\(x=\dfrac{2}{3}+\dfrac{4}{9}\)
\(x=\dfrac{10}{9}\)
d/\(\dfrac{3}{5}\times x-\dfrac{1}{2}=\dfrac{1}{5}\)
\(\dfrac{3}{5}\times x=\dfrac{1}{5}+\dfrac{1}{2}\)
\(\dfrac{3}{5}\times x=\dfrac{7}{10}\)
\(x=\dfrac{7}{10}:\dfrac{3}{5}\)
\(x=\dfrac{7}{6}\)

a,x=\(\dfrac{17}{6}\)b,x=\(\dfrac{5}{6}\)c,x=\(\dfrac{10}{9}\)d,x=\(\dfrac{7}{6}\)

Câu 6: Khôg có cau nào đúng

Câu 7: C

Câu 8: B

Câu 9: B

Câu 10: D

6Không có đáp án nào đúng x=11/4

7C

8B

9B

10D

a) \(\dfrac{1}{2}+x=\dfrac{5}{6}\)

\(\Rightarrow x=\dfrac{5}{6}-\dfrac{1}{2}=\dfrac{5}{6}-\dfrac{3}{6}=\dfrac{2}{6}=\dfrac{1}{3}\)

b) \(x+\dfrac{1}{4}=\dfrac{3}{4}\)

\(\Rightarrow x=\dfrac{3}{4}-\dfrac{1}{4}=\dfrac{2}{4}=\dfrac{1}{2}\)

c) \(x-\dfrac{1}{5}=\dfrac{3}{10}\)

\(\Rightarrow x=\dfrac{3}{10}+\dfrac{1}{5}=\dfrac{3}{10}+\dfrac{2}{10}=\dfrac{5}{10}=\dfrac{1}{2}\)

d) \(\dfrac{5}{6}-x=\dfrac{1}{3}\)

\(\Rightarrow x=\dfrac{5}{6}-\dfrac{1}{3}=\dfrac{5}{6}-\dfrac{2}{6}=\dfrac{3}{6}=\dfrac{1}{2}\)

e) \(\dfrac{3}{10}+x=\dfrac{1}{2}\)

\(\Rightarrow x=\dfrac{1}{2}-\dfrac{3}{10}=\dfrac{5}{10}-\dfrac{3}{10}=\dfrac{2}{10}=\dfrac{1}{5}\)

g) \(x+\dfrac{1}{4}=\dfrac{3}{8}\)

\(\Rightarrow x=\dfrac{3}{8}-\dfrac{1}{4}=\dfrac{3}{8}-\dfrac{2}{8}=\dfrac{1}{8}\)

a) ⇒x=56−12=56−36=26=13⇒x=56−12=56−36=26=13

b) ⇒x=34−14=24=12⇒x=34−14=24=12

c) ⇒x=310+15=310+210=510=12⇒x=310+15=310+210=510=12

d) ⇒x=56−13=56−26=36=12⇒x=56−13=56−26=36=12

e) ⇒x=12−310=510−310=210=15⇒x=12−310=510−310=210=15

g) ⇒x=38−14=38−28=18⇒x=38−14=38−28=18

Đọc tiếp

a) ⇒x=56−12=56−36=26=13⇒x=56−12=56−36=26=13

b) ⇒x=34−14=24=12⇒x=34−14=24=12

c) ⇒x=310+15=310+210=510=12⇒x=310+15=310+210=510=12

d) ⇒x=56−13=56−26=36=12⇒x=56−13=56−26=36=12

e) ⇒x=12−310=510−310=210=15⇒x=12−310=510−310=210=15

g) ⇒x=38−14=38−28=18⇒x=38−14=38−28=18

1) \(5-\left(1+\dfrac{1}{3}\right):\left(1-\dfrac{1}{3}\right)\)

\(=5-\dfrac{4}{3}:\dfrac{2}{3}\)

\(=5-\dfrac{4}{3}\cdot\dfrac{3}{2}\)

\(=5-\dfrac{4}{2}\)

\(=5-2\)

\(=3\)

b) \(\left(1+\dfrac{2}{3}-\dfrac{5}{4}\right)-\left(1-\dfrac{5}{4}\right)+2022-\dfrac{2}{3}\)

\(=1+\dfrac{2}{3}-\dfrac{5}{4}-1+\dfrac{5}{4}++2022-\dfrac{2}{3}\)

\(=\left(1-1\right)+\left(\dfrac{2}{3}-\dfrac{2}{3}\right)+\left(-\dfrac{5}{4}+\dfrac{5}{4}\right)+2022\)

\(=0+0+0+2022\)

\(=2022\)

2) \(0,7^2\cdot x=0,49^2\)

\(\Rightarrow x=\dfrac{0,49^2}{0,7^2}\)

\(\Rightarrow x=\left(\dfrac{0,49}{0,7}\right)^2\)

\(\Rightarrow x=\left(0,7\right)^2\)

\(\Rightarrow x=0,49\)

b) \(x:\left(-0,5\right)^3=\left(0,5\right)^2\)

\(\Rightarrow x=\left(0,5\right)^2\cdot\left(-0,5\right)^3\)

\(\Rightarrow x=\left(-0,5\right)^5\)

\(\Rightarrow x=-\dfrac{1}{32}\)

2:

a: =>x*0,49=0,49^2

=>x=0,49

b: =>x=(0,5)^2*(-1)*(0,5)^3=-(0,5)^5

a )\(A=\frac{x^2+4x+4}{x^2-4}=\frac{\left(x+2\right)^2}{x^2-2^2}=\frac{\left(x+2\right)^2}{\left(x+2\right)\left(x-2\right)}=\frac{x+2}{x-2}=\frac{5}{3}\)

<=> (x + 2).3 = (x - 2).5

<=> 3x + 6 = 5x - 10

<=> 3x - 5x = - 10 - 6

<=> - 2x = - 16

=> x = 8

b ) \(\frac{x+2}{x-2}=\frac{\left(x-2\right)+4}{x-2}=1+\frac{4}{x-2}\)

đến đây tự tìm đc 

Bài 2 lớp 8 ko làm đc thì đi chết đi

k mk đi

ai k mk

mk k lại

thanks