i need help with these questions

1. Among all rectangles having a perimeter 10ft. Find the dimensions, create the area of this function and find max. 2. In a rectangle, the perimeter is 60 and width is x then find a) Express length b) Create the area function c) Find the maximum 3. Suppose that a baseball is tossed straight up and that its height as a function of time is given by the formula: h = -161 + 64t + 6 In this formula, h is measured in feet and t is in seconds, with t = 0 corresponding to the instant that the ball is released. What is the maximum height of the ball? 4. Two numbers add to 5. What is the largest possible value for their product