The domain is this GIVEN interval -5 <= x <= 7 from -5 to 7, inclusive. In the interval form, it is the set [-5,7]. The function f(x) = 2x is a linear function, monotonically increasing. Therefore, its range is the interval between f(-5) = 2*(-5) = -10 and f(7) = 2*7 = 14. ANSWER. The domain is the interval [-5,7]. The range is the interval [-10,14].