f) (2x + 2 4/5) : 3 1/8 = 1 3/5`

`2x + 2 4/5 = 1 3/5 . 3 1/8`

`2x + 2 4/5 = 5`

`2x = 5 - 2 4/5`

`2x = 11/5`

`x = 11/5 : 2 

`x = 11/10`

Vậy `x = 11/10`

j) `2/3x - 3/7(1 - x) = 20/7`

`2/3x - 3/7 + 3/7x = 20/7`

`x (2/3 + 3/7) = 20/7 + 3/7`

`23/21x = 23/7`

`x = 23/7 : 23/21`

`x = 3`

Vậy `x = 3`.

k) `((3x)/7 + 1) : (-4) = -1/28`

`(3x)/7 + 1 = -1/28 . (-4)`

`(3x)/7 + 1 = 1/7`

`(3x)/7 = 1/7 - 1`

`(3x)/7 = -6/7`

`=> 21x = -42`

`=> x = -2`

Vậy `x = -2`.

l) `|x - 3| = 7`

`=> x - 3 = 7` hoặc `x - 3 = -7`

`=> x = 10` hoặc `x = -4`

Vậy `x ∈ {-4 ; 10}`

m) `(15/10x + 25) : 2/3 = 60`

`15/10x + 25 = 60 . 2/3`

`15/10x + 25 = 40`

`15/10x = 40 - 25`

`15/10x = 15`

`x = 15 : 15/10`

`x = 10`

Vậy `x = 10`.

n) `(2/3 - 1/2 : x) . 31/4 + 1/2 = -2 3/5`

`(2/3 - 1/2 : x) . 31/4 = -3,1`

`2/3 - 1/2 : x = -0,4`

`1/2x = 16/15`

`x = 15/32`

Vậy `x = 15/32`.

o) `x(1/2 - 15%) - 9/18 = 32/24`

`0,35x = 11/6`

`x = 110/21`

Vậy `x = 110/21`

p) x : 2 - 3/5 = 2 2/7 . 14/3`

`x : 2 - 3/5 = 32/3`

`x : 2 = 169/15`

`x = 338/15`

Vậy `x = 338/15`

$\rm j) \\ \dfrac{2}{3}x-\dfrac{3}{7}(1-x)=\dfrac{20}{7} \\ ⇒\dfrac{2}{3}x+\dfrac{3}{7}x-\dfrac{3}{7}=\dfrac{20}{7}\\⇒\dfrac{2}{3}x+\dfrac{3}{7}x=\dfrac{20}{7}+\dfrac{3}{7}\\⇒\dfrac{23}{21}x=\dfrac{23}{7}\\⇒x=\dfrac{23}{7}: \dfrac{23}{21}\\⇒x=3\\Vậy \ x=3\\k)\\ (\dfrac{3x}{7}+1):(-4)=\dfrac{-1}{28}\\⇒\dfrac{3x}{7}+1=\dfrac{1}{7}\\⇒\dfrac{3x}{7}=\dfrac{-6}{7}\\⇒3x=-6\\⇒x=-2\\Vậy\ x=-2\\m)\\(\dfrac{15}{10}x+25):\dfrac{2}{3}=60\\⇒\dfrac{15}{10}x+25 =60 . \dfrac{2}{3}\\⇒\dfrac{3}{2}x+25=40\\⇒\dfrac{3}{2}x=40-25=15\\⇒x=15:\dfrac{3}{2}\\⇒x=10\\Vậy \ x=10\\n)\\(\dfrac{2}{3}-\dfrac{1}{2}:x).\dfrac{31}{4}+\dfrac{1}{2}=-2\dfrac{3}{5}\\⇒(\dfrac{2}{3}-\dfrac{1}{2}:x).\dfrac{31}{4}=-2\dfrac{3}{5}-\dfrac{1}{2}\\⇒(\dfrac{2}{3}-\dfrac{1}{2}:x).\dfrac{31}{4}=-\dfrac{31}{10}\\⇒\dfrac{2}{3}-\dfrac{1}{2}:x=-\dfrac{31}{10}:\dfrac{31}{4}\\⇒\dfrac{2}{3}-\dfrac{1}{2}:x=-\dfrac{2}{5}\\⇒\dfrac{1}{2}:x=\dfrac{2}{3}-(-\dfrac{2}{5})\\⇒\dfrac{1}{2}:x=\dfrac{16}{15}\\⇒x=\dfrac{1}{2}:\dfrac{16}{15}\\⇒x=\dfrac{15}{32}\\Vậy \ x=\dfrac{15}{32}\\p)\\x:2-\dfrac{3}{5}=2\dfrac{2}{7}.\dfrac{14}{3}\\⇒x:2-\dfrac{3}{5}=\dfrac{32}{3}\\⇒x:2=\dfrac{169}{15}\\⇒x=\dfrac{338}{15}\\Vậy \ x=\dfrac{338}{15}\rm $