Bài 2:
`a)3/15 .(-5)/(-6)=[3.(-5)]/[3.(-5).(-1).(-6)]=1/6`
`b)[(-6).7]/[7.(-8)]=[2.(-3).7]/[7.2.(-4)]=(-3)/(-4)=3/4`
`c)[9.(-13)]/[13.(-12)]=[3.3.13.(-1)]/[13.4.3.(-1)]=3/4`
`d)[(-21).(-5)]/[15.(-7)]=[7.3.5.(-1).(-1)]/[5.3.7.(-1)]=-1`
`e)(32.9.11)/(12.24.22)=(4.8.3.3.11)/(3.4.6.4.11.2)=1/2`
Bài 3:
`a)`
`6/8=18/24=36/48`
`(-12)/15=(-24)/30=(-40)/50`
`b)`
`(-6)/(-10)=36/60`
`10/12=30/36`
`(-25)/35=15/(-21)`
