1) |x+1| = 2
⇒\(\left[ \begin{array}{l}x+1=2⇔x=1\\x+1=-2⇔x=-3\end{array} \right.\)
2) |x – 2| = 3
⇒\(\left[ \begin{array}{l}x-2=3⇔x=5\\x-2=-3⇔x=-1\end{array} \right.\)
3) x +|-2| = 0
⇒x +2=0
x =0-2
x =-2
4) 72 – 3.|x + 1| = 9
3.|x + 1| =72-9
3.|x + 1| =63
|x + 1| =63 : 3
|x + 1| =21
⇒\(\left[ \begin{array}{l}x+1=21⇔x=20\\x+1=-21⇔x=-22\end{array} \right.\)