Step-by-step explanation:
a). A = {x  ∈ R  I  5x-8 < 7}
5x - 8 < 7 <=> 5x < 8+7  <=> 5x < 15  =>
x < 3  => A = (-∞ ; 3) 
A ∩ N = {0 ; 1 ; 2}
A - N* = (-∞ ; 3) - {1 ; 2}
b).  A = { x ∈ R  I  7x+2 ≤ 9} 
7x+2 ≤ 9 <=> 7x ≤ 7  => x ≤ 1 => x ∈ (-∞ ; 1]
A ∩ N = {0 ; 1}
A-N* = (-∞ ; 1)
c).  A = { x ∈ R  I  I 2x-1 I < 5} 
I 2x-1 I < 5  <=> -5 ≤ 2x-1 ≤ 5  <=>
-4 ≤ 2x ≤ 6  <=> -2 ≤ x ≤ 3  => x ∈ [-2 ; 3]
A ∩ N = {0 ; 1 ; 2 ; 3}
A - N* = [-2 ; 3) - {1 ; 2}
d).  A = {x ∈ R I I 6-3x I ≤ 9}
I 6-3x I ≤ 9  <=> -9 ≤ 6-3x ≤ 9  <=>
-15 ≤ -3x ≤ 3 <=> -5 ≤ -x ≤ 3  =>
-3 ≤ x ≤ 5  => x ∈ [-3 ; 5]
A ∩ N = {0 ; 1 ; 2 ; 3 ; 4 ; 5}
A - N* = [-3 ; 5) - {1 ; 2 ; 3 ; 4}