Question

Exercitiul 2 din aceasta poza...va rog frumos :) 

Answer 1

a) -4/x ∈ Z . 
⇒x = { 1 , -1 , 2 , -2 , 4 , -4 } . 

7/2x-1 , ∈ Z 
⇒2x-1 ={1,-1,7,-7}

⇒2x-1=-1
  2x=0
x=0 . 

2x-1=1
2x=2
x=1

2x-1=7
2x=8
x=4   

2x-1=-7
2x=-6
x=-3 .   ⇒ x ∈ {-3,0,1,4} . 

c)-8/2x-1 ∈ Z 

⇒2x-1 ={1,-1,2,-2,4,-4,8,-8}

2x-1=-1
2x=0
x=0

2x-1=1
2x=2
x=1

2x-1=-2
2x=-1
x=-1/2

2x-1=2
2x=3
x=3/2

2x-1=-4
2x=-3
x=-3/2

2x-1=4
2x=5
x=5/2

2x-1=-8
2x=-7
2x=-7/2

2x-1=8
2x=9
x=9/2    ⇒ x∈{0,1,-1/2,3/2,-3/2,5/2,-7/2,9/2}