I have two problems (listed below):

1.The profit P (in hundreds of dollars) that a company makes depends on the amount x (in hundreds of dollars) the company spends on advertising according to the model P = 230 + 20x -0.5x^2.

What expenditure for advertising will yield a maximum profit?

2. The height y (in feet) of a ball thrown by a child is y= -1x^2/12 + 2x + 4, where x is the horizontal distance (in feet) from the point at which the ball is thrown.

How far from the child does the ball strike the ground?