They say it is the number of the thousands of pairs you produce cubed minus six times the thousands of pairs you produce squared plus 15 times the thousands of pairs that you produce. And once again, this is going to be, this is also going to be in thousands of dollars. Now, given these functions of x for revenue and cost, what is profit as a function of x going to be? Well, your profit as a function of x is just going to be equal to your revenue as a function of x minus your cost as a function of x. Minus your cost as a function of x. If you produce a certain amount, and let's say you bring in, I don't know, $10,000 of revenue and it costs you $5,000 to produce those shoes, you'll have $5,000 in profit. Those numbers aren't the ones that would actually, you would get from this right here.