The rate of change can be described as the slope, or how much the y-value is going to change as the x-value increases by 1. So the first step would be to understand what is x and what is y in this context. Well usually y is the dependent variable and x is the independent variable, so as x changes y changes as a result. In this case the y would represent the price the repair person charges and the x would represent the amount of hours, since as the amount of hours changes, the price changes. And since the person charges 30$ per hour, that means the rate of change is 30, since as the amount of hours increases by 1, the price or amount charged increases by 30$
