a, 7\(\dfrac{3}{5}\) : \(x\) = 5\(\dfrac{4}{15}\) - 1\(\dfrac{1}{6}\)

     \(\dfrac{38}{5}\) : \(x\) = \(\dfrac{79}{15}\) - \(\dfrac{7}{6}\)

              \(x\) = \(\dfrac{41}{10}\)

             \(x\) = \(\dfrac{38}{5}\) : \(\dfrac{41}{10}\)

              \(x\) = \(\dfrac{76}{41}\)

b, \(x\) \(\times\) 2\(\dfrac{2}{3}\) = 3\(\dfrac{4}{8}\) + 6\(\dfrac{5}{12}\)

    \(x\) \(\times\) \(\dfrac{8}{3}\)  = \(\dfrac{7}{2}\) + \(\dfrac{77}{12}\)

     \(x\) \(\times\) \(\dfrac{8}{3}\) = \(\dfrac{119}{12}\)

     \(x\)          = \(\dfrac{119}{12}\)

     \(x\)          = \(\dfrac{119}{12}\): \(\dfrac{8}{3}\)

     \(x\)           = \(\dfrac{119}{32}\)

`1/2 xx 1/3 xx 1/4`

`= (1xx1xx1)/(2xx3xx4)`

`= 1/24`

__

`1/2 xx 1/3 : 1/4`

`= 1/2 xx 1/3 xx 4`

`= (1xx1xx4)/(2xx3)`

`= 4/6`

`=2/3`

__

`1/2 : 1/3 xx1/4`

`= 1/2 xx 3 xx 1/4`

`=(1xx3xx1)/(2xx4)`

`= 3/8`

__

`1/2 : 1/3 : 1/4`

`= 1/2 xx 3xx4`

`= 12/2`

`=6`

`1/2xx1/3xx1/4`

`=1/24`

`1/2xx1/3:1/4`

`=1/6xx4`

`=4/6=2/3`

`1/2:1/3xx1/4`

`=1/2xx3xx1/4`

`=3/2xx1/4`

`=3/8`

`1/2:1/3:1/4`

`=1/2xx3xx4`

`=6`

=6

cho tớ không

1^3-3^5-(-3^5)+1^64-2^9-1^36+1^15

=1+(-3^5+3^5)+1-2^9-1+1

=2-2^9

=-510

7/4

62/72

1/3

5/2

5/2-3/4=7/4

5/2 - 3/4 =20/8-6/8=14/8

1/9+6/8=8/72+54/72=62/72

2/3-1/3=1/3

4/2+1/2=5/2

1/3+1/4+1/5+/12/15+22/33+48/64

=1/3+1/4+1/5+4/5+2/3+3/4

=3

dung 100% luon 

Ai k cho minh 3 k thi minh se k cho nguoi ay 5 k 

\(=\frac{7}{12}+1+\frac{17}{12}\)

\(=2+1\)

\(=3\)

Hok giỏi nghen 

~~~~~~~~~~

\(\frac{48}{64}=\frac{3}{4}\);\(\frac{22}{33}=\frac{2}{3}\);\(\frac{12}{15}=\frac{4}{5}\)

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

=1 + 1 + 1 

= 3

\(B=2+2^2+2^3+...+2^{2016}\)

\(2B=2^2+2^3+...+2^{2017}\)

\(B=2^{2017}-2\)

các ý khác tương tự 

ý C nhân vs 3

   D                4

  E                5

3C = 3(1+3+3^2+.......+3^2017)

= 3+3^2+3^3+......+3^2018

3C - C = (3+3^2+3^3+......+3^2018) - (1+3+3^2+......+3^2017)

= 3^2018 - 1

=> C = (3^2018 - 1) : 2

còn lại tự làm nhé

A= 1+2+2²+2³+2⁴ / 1+2+2²+2³=2⁰+....+2⁴/ 2⁰+....+2³

=>rút gọn vế trái và vế phải ta được kết quả là ;2⁴=16

B thì làm tương tự bài trên

chúc bạn họ tốt !

\(A=\frac{\left(1+2+2^2+2^3+2^4\right)}{\left(1+2+2^2+2^3\right)}\)

\(A=\frac{2^4\left(1+2+2^2+2^3\right)}{\left(1+2+2^2+2^3\right)}\)

\(A=2^4=16\)

\(B=\frac{\left(1+3+3^2+3^3+3^4\right)}{\left(1+3+3^2+3^3\right)}\)

\(B=\frac{3^4\left(1+3+3^2+3^3\right)}{\left(1+3+3^2+3^3\right)}\)

\(B=3^4=81\)

\(\text{Ta co }A=16< B=81\)

\(\Rightarrow A< B\)

Ta có:

A = \(\frac{1+2+2^2+2^3+2^4}{1+2+2^2+2^3}=\frac{\left(1+2+2^2+2^3\right)+2^4}{1+2+2^2+2^3}\)

  = \(1+\frac{2^4}{1+2+2^2+2^3}=1+\frac{\left(1+2+2^2+2^3\right)+1}{1+2+2^2+2^3}\)

 = \(1+1+\frac{1}{1+2+2^2+2^3}=2+\frac{1}{1+2+2^2+2^3}\)

B = \(\frac{1+3+3^2+3^3+3^4}{1+3+3^2+3^3}=\frac{\left(1+3+3^2+3^3\right)+3^4}{1+3+3^2+3^3}\)

  = \(1+\frac{3^4}{1+3+3^2+3^3}=1+\frac{\left(1+3+3^2+3^3\right).2+1}{1+3+3^2+3^3}\)

 = \(1+2+\frac{1}{1+3+3^2+3^3}=3+\frac{1}{1+3+3^2+3^3}\)

Ta thấy : 2 < 3 => \(2+\frac{1}{1+2+2^2+2^3}< 3+\frac{1}{1+3+3^2+3^3}\)

=> A < B