a) -3x = -5 + 29
⇒ -3x = 24
⇒ x = 24 : (-3) = -8
Vậy x = -8
b) |x| - 9 = -2
⇒ |x| = -2 + 9 = 7
⇒ \(\left[ \begin{array}{l}x=7\\x=-7\end{array} \right.\)
Vậy x ∈ {7; -7}
c) |x - 9| = -2 + 17
⇒ |x - 9| = 15
⇒ \(\left[ \begin{array}{l}x-9=15\\x-9=-15\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x=15+9\\x=-15+9\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x=24\\x=-6\end{array} \right.\)
Vậy x ∈ {24; -6}
