Need help with these problems Thanks in Advance!!

1. Find the critical point(s) of the function f (x) =12x-x2. 2. The function defined by f (x) = x) -3x -2 has a relative minimum at X = 3. What is the x-coordinate of the point of inflection on the graph of y = =x -3x2 +24? 3. li 4. Given the function defined by f (x)=-2x3 +6x3 -3, find all values of x for which the graph of f is concave Whic down. Remo