d) x ≤ -8/2
x≤ -4 => x∈(-∞, -4]
e) x> -6 => x∈ (-6,+∞)
f) x≤ 2 => x∈ (-∞,2]
g) x> 0 => x∈ (0,∞)
h) x≤0 => x∈ (-∞,0]
