`1) 5.|x - 3| = 5/7`
`-> |x - 3| = 5/7 : 5`
`-> |x - 3| = 1/7`
$\text{Trường hợp 1:}$
`x - 3 = 5/7`
`x` `= 5/7 + 3`
`x` `= 26/7`
$\text{Trường hợp 2:}$
`x - 3 = -5/7`
`x` `= -5/7 + 3`
`x` `= 16/7`
Vậy `x ∈ {26/7; 16/7}`
`3) 1/2.|x + 5| = 3/2`
`-> |x + 5| = 3/2 : 1/2`
`-> |x + 5| = 3`
$\text{Trường hợp 1:}$
`x + 5 = 3`
`x` `= 3 - 5`
`x` `= -2`
$\text{Trường hợp 2:}$
`x + 5 = -3`
`x` `= -3 - 5`
`x` `= -8`
Vậy `x ∈ {-2; -8}`
`5) -3/7.|x - 7| = -9/14`
`-> |x - 7| = (-9/14) : (-3/7)`
`-> |x - 7| = 6/7`
$\text{Trường hợp 1:}$
`x - 7 = 6/7`
`x` `= 6/7 + 7`
`x` `= 55/7`
$\text{Trường hợp 2:}$
`x - 7 = -6/7`
`x` `= -6/7 + 7`
`x` `= 43/7`
Vậy `x ∈ {43/7; 2/3}`
`7) 4/5.|x - 2| = 8/15`
`-> |x - 2| = 8/15 : 4/5`
`-> |x - 2| = 2/3`
$\text{Trường hợp 1:}$
`x - 2 = 2/3`
`x` `= 2/3 + 2`
`x` `= 8/3`
$\text{Trường hợp 2:}$
`x - 2 = -2/3`
`x` `= -2/3 + 2`
`x` `= 4/3`
Vậy `x ∈ {8/3; 4/3}`
`9) -2.|3.x + 1| = -4/3`
`-> |3.x + 1| = (-4/3) : (-2)`
`-> |3.x + 1| = 2/3`
$\text{Trường hợp 1:}$
`3.x + 1 = 2/3`
`3.x` `= 2/3 - 1`
`3.x` `= -1/3`
`x` `= (-1/3) : 3`
`x` `= -1/9`
$\text{Trường hợp 2:}$
`3.x + 1 = -2/3`
`3.x` `= (-2/3) - 1`
`3.x` `= -5/3`
`x` `= (-5/3) : 3`
`x` `= -5/9`
Vậy `x ∈ {-1/9; -5/9}`
@Vy
