Need help solving these practice questions

The function P(y) = 0.011y- -3.146y + 252.450 represents the population P (in millions) of people in 2005 that were y years of age or older. (a) Identify the dependent and independent variable. The dependent variable is P and the independent variable is y. O The dependent variable is y and the independent variable is P. (b) Evaluate P(50). P(50) = (Round to three decimal places as needed.)If an object is thrown upward with an initial velocity of 64 ft/second, then its height after t seconds is given by the following equation. h = 64t - 3212 a. Find the maximum height attained by the object. b. Find the number of seconds it takes the object to hit the ground. a. The maximum height attained by the object is 3 feet