Răspuns :
x + 1 < 5
x < 4
x ∈ [0, 4) ∩ N
2x - 4 ≤ 8
2x ≤ 12
x ≤ 6
x ∈ [0, 6] ∩ N
3x + 1 < 1
3x < 0
x < 0
x ∈ (-oo, 0) ∉ N
Răspuns:
Explicație pas cu pas:
a) x+1 < 5 <=> x < 5-1 <=> x<4 => x ∈ {0,1,2,3}
b) 2x-4 ≤ 8 <=> 2x≤8+4 <=> 2x ≤ 12 <=> x≤12:2 <=> x≤6 =>
x∈{0,1,2,3,4,5,6}
c) 3x+1<1 <=> 3x < 1-1 <=> 3x<0 => x<0 => x∈{∅}