1) 8+ |x| =|-8| +11
⇔ 8+ |x|= 8+11
⇔ 8+ |x|=19
⇔ |x| =11
⇔ \(\left[ \begin{array}{l}x=11\\x=-11\end{array} \right.\)
vậy x ∈ {-11;11}
2) |x|+ 45 = |-17|+|-28|
⇔ |x|+45=17+28
⇔ |x|+45=45
⇔ |x| =0
⇔ x =0
Vậy x=0
3) |x-2| =-|-3|+|9|
⇔ |x-2|= -3+9
⇔ |x-2|= 6
⇔\(\left[ \begin{array}{l}x-2=6\\x-2=-6\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=8\\x=-4\end{array} \right.\)
Vậy x ∈ {8;-4}
