Luyện tập

`3 : 6/5`

`= 3 xx 5/6`

`= 15/6`

__

`4 : 6/7`

`= 4 xx 7/6`

`= 28/6`

`= 14/3`

__

`x xx 11/8=33/20`

`=> x= 33/20 : 11/8`

`=> x= 33/20 xx 8/11`

`=>x=6/5`

__

`5 : x =4/7`

`=> x= 5 : 4/7`

`=> x= 5 xx 7/4`

`=> x= 35/4`

`2/3xx4=(2xx4)/3=8/3`

`=>B`

B)

`10/3:5/6=10/3xx6/5=4`

`=>C

C)

`12:6/5+4/7`

`=12xx5/6+4/7`

`=10+4/7`

`=70/7+4/7`

`=74/7`

`=>B`

`3/5+4/7`

`=21/35+20/35`

`=41/35`

\(\dfrac{3}{5}+\dfrac{4}{7}=\dfrac{21}{35}+\dfrac{20}{35}=\dfrac{41}{35}\)

\(\dfrac{3}{5}+\dfrac{4}{7}\left(MC:35\right)\\ =\dfrac{3\times7}{5\times7}+\dfrac{4\times5}{7\times5}\\ =\dfrac{21}{35}+\dfrac{20}{35}\\ =\dfrac{41}{35}.\)

`( 13/12 + 4/3) : 2/3`

`= ( 13/12 + 16/12 ) : 2/3`

`= 29/12 : 2/3`

`= 29/12 xx 3/2`

`=29/8`

__ 

`( 5/6 - 3/8) x 2 1/2`

`=(40/48 - 18/48) xx 5/2`

`=11/24 xx 5/2`

`=55/48`