Question

What are the domain and range of f(x) = 2(3x)?
domain: (negative infinity, infinity); range: (0, infinity)
domain: (negative infinity, infinity); range: (2, infinity)
domain: (0, infinity); range: (negative infinity, infinity)
domain: (2, infinity); range: (negative infinity, infinity)

Answer 1

Assuming the function is exponential f(x) = 2^{3x}, the domain is all real numbers and the range is all positive real numbers:

domain: (-∞, ∞); range: (0, ∞)

(If instead you meant f(x) = 2(3x) = 6x, then domain and range would both be (-∞, ∞).)