Interpreting Linear and Exponential Functions Arising in Applications
One day Jim sees that he can upgrade his phone service. He can't decide whether to go with the plan that is 40 dollars a month plus 80 cents per text or the plan that is cost is 50 dollars a month plus 50 cents per text. They both sound like a good deal to him but in the end he chooses the plan that is 40 dollars a month plus 80 cents per text. The function for his plan is f(x)= .80x + 40. The y-intercept would be where he makes no texts so his cost would only be 40$. In this situation, there is no x-intercept. The function is increasing buy 80 cents. It cant decrease in this case and all of his monthly costs will be positive. This functions end behavior is 40 increasing infinity. The least he can pay a month is 40$ so that is where the graph starts.
The Domain for my function is all real whole positive numbers because you can't send 1/2 a text, so all whole real numbers can be inputted.
The rate of change for a linear function is f(x)= x,but in my case there is a y-intercept of 40 and the rate of change is .80.