`a) |x+1/3|-5=7`
`=> |x+1/3| = 7 + 5`
`=> |x+1/3| = 12`
`=> x + 1/3 = 12` hoặc `x + 1/3 = -12`
`+) x + 1/3 = 12`
`=> x = 12 - 1/3`
`=> x = 35/3`
`+)x + 1/3 = -12`
`=> x = -12 - 1/3`
`=> x = (-37)/3`
Vậy `x \in{ 35/3 ; (-37)/3 }`
`b) 3 . (x-2) + 2/5 = 4`
`=> 3 . (x-2) = 4 - 2/5`
`=> 3 . (x-2) = 18/5`
`=> x - 2 = 18/5 : 3`
`=> x - 2 = 6/5`
`=> x = 6/5 + 2`
`=> x = 16/5`
Vậy `x = 16/5`
