A = {x ∈ ℕ⏐2ˣ⁺² ≤ 4²}
B = {y ∈ ℕ⏐ y = 2-x, x ∈ A}
A: 2ˣ⁺² ≤ 4² ⇔ 2ˣ⁺² ≤ (2²)² ⇔ 2ˣ⁺² ≤ 2⁴
⇔ x+2 ≤ 4 ⇔ x ≤ 4-2 ⇔ x ≤ 2
⇒ A = {0, 1, 2}
B: y ∈ {2-0, 2-1, 2-2) ⇔ y ∈ {2, 1, 0}
⇒ B = {0, 1, 2}
