Question

Bài 21:  Cộng các phân số sau

\(\dfrac{36}{-84}\) +\(\dfrac{100}{450}\)              \(\dfrac{-650}{1430}\)+\(\dfrac{588}{686}\)                   \(\dfrac{2004}{2010}\)+\(\dfrac{8}{-670}\)

Trình bày đầy đủ nhe mn mik cần gấp

ai lm mik tích cho

Answer 1

a: \(=\dfrac{-3}{7}+\dfrac{2}{9}=\dfrac{-27+14}{63}=\dfrac{-13}{63}\)

b: \(=\dfrac{-5}{11}+\dfrac{6}{7}=\dfrac{-35+66}{77}=\dfrac{31}{77}\)

c: \(=\dfrac{2004-24}{2010}=\dfrac{1980}{2010}=\dfrac{66}{67}\)

Answer 2

\(\dfrac{36}{-84}+\dfrac{100}{450}=-\dfrac{3}{7}+\dfrac{2}{9}=\dfrac{-27}{63}+\dfrac{14}{63}=\dfrac{-27+14}{63}=-\dfrac{13}{63}\)

\(-\dfrac{650}{1430}+\dfrac{588}{686}=\dfrac{-5}{11}+\dfrac{6}{7}=\dfrac{-35}{77}+\dfrac{66}{77}=\dfrac{-35+66}{77}=\dfrac{31}{77}\)

\(\dfrac{2004}{2010}+\dfrac{8}{-670}=\dfrac{334}{335}-\dfrac{4}{335}=\dfrac{334-4}{335}=\dfrac{330}{335}=\dfrac{66}{67}\)

 

 

Answer 3

`36/(-84) + 100/450`

`=(-3)/7 + 2/9`

`=(-27)/63 + 14/63`

`=(-13)/63`

--------------------------------------------------------

`(-650)/1430 + 588/686`

`= (-5)/11 + 6/7`

`= (-35)/77 + 66/77`

`= 33/77`

___________________________________

`2004/2010 + 8/(-670)`

`=334/335 - 4/335

`= 330/335`

`=66/67`