5/6 x 1/7 - 1/7 x 1/6
= 1/7 x (5/6 - 1/6)
= 1/7 x 2/3
= 2/21
8/15 : 4/5 x 3/2
= 2/3 x 3/2
= 1
a: =1/7(5/6-1/6)=1/7x2/3=2/21
b: =8/15x5/4x3/2=1
`5/6xx1/7-1/7xx1/6`
`= 1/7 xx (5/6-1/6)`
`= 1/7 xx 2/3`
`= 2/21`
`8/15: 4/5 xx3/2`
`= 2/3 xx 3/2`
`= 1`
\(\dfrac{5}{6}\times\dfrac{1}{7}-\dfrac{1}{7}\times\dfrac{1}{6}=\left(\dfrac{5}{6}-\dfrac{1}{6}\right)\times\dfrac{1}{7}=\dfrac{4}{6}\times\dfrac{1}{7}=\dfrac{2}{3}\times\dfrac{1}{7}=\dfrac{2}{21}\)
\(\dfrac{8}{15}:\dfrac{4}{5}\times\dfrac{3}{2}=\dfrac{8}{15}\times\dfrac{5}{4}\times\dfrac{3}{2}=\dfrac{40}{60}\times\dfrac{3}{2}=\dfrac{20}{20}=1\)
5/6x1/7-1/7x1/6
=1/7 x ( 5/6 - 1/6 )
= 1/7 x 2/3
= 2/21
8/15:4/5x3/2
= 8/15 x 5/4 x 3/2
= 2/3 x 3/2
= 1
=1/7x(5/6-1/6)
=1/7x4/6
=4/42
còn lại thì mình chịu
