Answer:
m = $25
Step-by-step explanation:
The equation that the plumber is using 'y = mx + b' represent a linear equation. A linear equation shows a relationship between two set of data where the change is constant. In the case of the plumber, his rate is $25 per hour, so for every hour, he charges the same amount. So, as each hour increases, the rate increases another $25. In the equation y = mx + b , y = the total (dependent variable), m = rate of change, x = the number of hours (independent variable) and b = initial value. The $45 fee is the initial value or charge regardless of the number of hours worked. So, m = $25, which is the rate per hour.
