College Algebra
(f - g)(x) = -x + 7; Domain: (-∞, ∞)
(f - g)(x) = x - 7; Domain: (-∞, ∞)
(f - g)(x) = x + 7; Domain: (-∞, ∞)
(f - g)(x) = -x - 7; Domain: [0, ∞)