Aplicam urmatoarea proprietate :
|[tex]x[/tex]| = [tex] \left \{ {{x , x \geq 0} \atop {-x,x<0}} \right. [/tex]
1. |[tex]5-x[/tex]| = [tex]7+x[/tex]
Cazul 1 :
[tex]5-x = 7 + x ==> 2x = -2 ==> x = -1[/tex]
Cazul 2 :
[tex]5-x = -7-x ==> 5 = -7 ==> Contradictie[/tex]
2.
|[tex]x-5[/tex]| < [tex]7-x[/tex]
Cazul 1 :
[tex]x-5<7-x ==> 2x<12==> x<6 [/tex]
Cazul 2:
[tex]x-5<-7+x ==> -5<-7 ==> Contradictie[/tex]
