Final answer:
The function y = 3x is a linear function because it fits the form y = a + bx with a constant rate of change, which represents the slope. There is no y-intercept mentioned, so it is implied to be 0, making the slope constant at 3.
Step-by-step explanation:
To determine if y = 3x is a linear function, we need to investigate its characteristics. A linear function can be identified by its form, which is y = a + bx, where a is the y-intercept and b is the slope of the line. In the equation y = 3x, there is no y-intercept explicitly mentioned, which implies that a = 0, and the coefficient of x, which is 3, represents the slope. Hence, we can see that y = 3x fits the form of a linear function, where the slope (b) is constant at 3, and the y-intercept (a) is 0. Therefore, the correct answer is: a) It has a constant rate of change, meaning that the function is indeed linear since it demonstrates a consistent increase in the value of y with each increase in x.