Financial analysts in a company that manufactures headphones arrived at the following daily cost function for $x$ number of headphones per day: $C(x)=x^2-2x+2000,x>0.$ Determine the minimum average cost of producing headphones, and give the number of headphones needed to produce a minimum average cost. $($Remember you cannot produce a fractional number of headphones$).$ Draw a picture of your friendly window.

How do i graph this on my graphing calculator?