`a ) x : 1/2 : 1/6 = 2 2/5`
`x : 1/2 : 1/6 = 12/5`
`x : 1/2 = 12/5 × 1/6`
`x : 1/2 = 2/5`
`x = 2/5 × 1/2`
`x = 1/5`
Vậy `x = 1/5`
`b ) x × 2/3 - 1/5 = 1 12/15`
`x × 2/3 - 1/5 = 27/15`
`x × 2/3 = 27/15 + 1/5`
`x × 2/3 = 2`
`x = 2 : 2/3`
`x = 3`
Vậy `x = 3`
`#dtkc`