12. Which of the following equations represents a quadratic function? a. The diagonal of a rectangle is 8 m longer than its shorter side. If the area of the rectangle is 60m2, find its dimensions. b. A car moves 50 kph, what is the distance traveled after 6 hours? c. The length of a rectangular garden is 8ft more than its width. What will be its dimensions? d. Mary is twenty-four. She is twice as old as Ann when Mary was as old as Ann now. How old is Ann? 13. A rectangular plot of ground is 120m long and 80m wide. To double the area of the plot, while retaining the rectangular shape, strips of equal width will be added at one end and along one side. What function will represent the problem? a. y = -4x2 + 4800 c. y = 2x2 + 100x -2400 b. y = x2 + 200x -9600 d. y = -2x2 + 400x -3200 13. Which of the following is the graph of f(x) = x2 + 4x + 3?
