A plumber charges 25$ for a service call plus 50$ per hour of service. write an equation for the cost, C, after h hours of service.

We know that C is dependent on how many hours of service was done. We also know that C is linearly dependent on how many hours of service was done because it's a constant $50 per hour.

So, the equation would be a linear equation in the form C = 50h + L where h is the number of hours and L is the y-intercept.

Since there is an initial charge of $25, when h = 0, C = $25 - > L = $25.

So, the equation is C = 50h + 25.