Sometimes when we are asked to write a linear model we are given descriptions of the rate of change and the starting value. With this we have enough information to write the linear model. Brooks is selling handmade soap at a downtown craft fair. He paid $60 to be at the craft fair and he sells the soap for $6 per bar. Write a model to represent his profits as a function of how many bars of soap he sells. s, the input, is the number of bars of soap Brooks sells. P, the output, is his profits from selling at the craft fair. The rate of change is :] The starting value is S