Bài 3
`-5/6`;`-3/4`;`7/24`;`2/3`;`7/8`
Bài 4
a) `1/2`*x+`2/3`*(x-1) = `1/3`
`1/2`*x+`2/3`*x-`2/3`=`1/3`
x*(`1/2`+`2/3`)-`2/3`=`1/3`
x*`7/6`-`2/3`=`1/3`
x*`7/6`=`1/3`+`2/3`
x*`7/6`=1
x= 1:`7/6`
x= 1*`6/7`
x= `6/7`
b) `2/3`*x:`1/5`=1`1/3`:25%
`2/3`*5*x=`4/3`*4
`10/3`*x=`16/3`
x=`16/3`:`10/3`
x=`16/3`*`3/10`
x=`48/30`=`16/10`