Question

Ajutorrr!!! Dau coroana la cel mai bun raspuns!
Determinati x€Z astfel incat:
-4supra x x€Z
7 supra 2x-1 €Z
-8 supra 2x-1€Z
Va rog rapid!!!

Answer 1

-4/x ∈Z=>xI-4=>x∈D(-4 )   D(-4)=divizorii lui -4  x∈{-4,-1,0,1,4}    ( I-4)divide pe -4
7/2x-1∈Z=>2x-1I 7 , 2x-1∈D(7)  D(7)=(-7,-1,0,1,7)
2x-1=-7=>2x= -7+1=>2x=-6 =>x=-6/2 ,X= -3
2x-1=-1=>2x=-1+1=>2x=0,x=0
2x-1=0=>2x=-1=>x=-1/2,x∉Z
2x-1=1    =>2x=2=>x=1
2x-1=7 =.2x=8 =>x=4
x∈{-3,0,1,4}
-8/2x-1∈Z =>2x-1 I -8  ,2x-1∈D(-8),2x-1∈{-8,-4,-2,-1,0,1,2,4,8]
2x-1=-8, ⇔2x=-7⇔x∉Z
2x-1=-4⇔2x=-3⇔x∉Z
2x-1=-1⇔2x=0⇔x=0
2x-1=1⇔2x=2⇔x=1
x∈{0,1}