Chapter 7 Exponential and Logarithmic Functions - 7.3 Use Functions Involving e - 7.3 Exercises - Skill Practice - Page 495: 12

$$\frac{4}{e^{3x}}$$

Though $e$ is the natural base, the same rules of exponents apply to $e$ as the rules that we learned in previous chapters. Thus, applying the rules of exponents, we find: $$4e^{x-4x}\\ \frac{4}{e^{3x}}$$