Răspunsuri

2014-10-26T12:03:08+02:00
Aplicam urmatoarea proprietate :

|x| =  \left \{ {{x , x \geq 0} \atop {-x,x<0}} \right.

1. |5-x| = 7+x
Cazul 1 :
5-x = 7 + x ==> 2x = -2 ==> x = -1
Cazul 2 :
5-x = -7-x ==> 5 = -7 ==> Contradictie

2.
|x-5| < 7-x
Cazul 1 :
x-5<7-x ==> 2x<12==> x<6
Cazul 2:
x-5<-7+x ==> -5<-7 ==> Contradictie