Rewrite this function in the form that reveals the minimum of the function. c(p)=p^2-28p+250

Given that the function is given by:
c(p)=p^2-28p+250
The minimum value of the function is at the derivative of c'(p)
thus from the function given:
c(p)=p^2-28p+250
c'(p)=2p-28
Thus the minimum function is c'(p)=2p-28

No i refuse to tell you the answer but the estimate is 10