`a, 1/3 x + 13 1/4 = 16 1/4`
`⇔ 1/3 x = 16 1/4 - 13 1/4`
`⇔ 1/3 x = 2`
`⇔ x = 2 : 1/3`
`⇔ x = 6 `
Vậy , `x = 6`
Vậy , ` x ∈ { 6 ; - 6 }`
`b, | x - 1/3 | - 0,5 = 7/12`
`⇔ | x - 1/3 | - 1/2 = 7/12`
`⇔ | x - 1/3 | = 7/12 + 1/2`
`⇔ | x - 1/3 | = 13/12`
`⇔` \(\left[ \begin{array}{l}x - 1/3 = 13/12\\x - 1/3 = - 13/12\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x = 17/12\\x = - 3/4\end{array} \right.\)
Vậy , `x ∈ { 17/12 ; ( - 3 )/4 }`