Final answer:
The amplitude of the wave equation y = 3 - 4sin(3x) is represented by the coefficient of the sine function, which is 4, making the correct answer a. 4.
Step-by-step explanation:
For a sinusoidal wave equation of the form y = A sin(Bx + C), the amplitude is given by the absolute value of coefficient A, which represents the maximum displacement of the wave from its equilibrium position. In the wave equation y = 3 - 4sin(3x), the amplitude is given by the coefficient in front of the sine function, which in this case, is 4. Since the amplitude is always positive, regardless of the sign of the coefficient in the equation, the correct answer is a. 4.