The daily profit off a custom Tshirt shop can be modeled by
     The daily profit off a custom T-shirt shop can be modeled by P(n) = n^2 + 60n-400, where and is the number of T-shirts produced each day and P(n) is The Profit made on that number. Rewrite this function in vertex form and determine the maximum daily profit. 
  
  Solution
P(n)=-n2+60n-400
P(n)=-(n2-60n)-400
P(n)=-(n2-60n+(-60/2)2-(-60/2)2)-400
P(n)=-(n2-60n+900-900)-400
P(n)=-(n2-60n+900)+900-400
P(n)=-(n-30)2+500
vertex is (30,500)
maximum daily profit =500

