X is equal to or greater than 10. What is annual profit?

You have a function P(x) which I assume is profit. The value of P depends on x, and they tell you that x \small \ge 10. You can plot a graph of P for x \small \ge , to show how P varies with x. You might start by seeing what P equals for x = 10, and then try a few more value of x to get a feel for how P behaves. Take a shot at it and post back with your findings.