Quadratic function word problems

Hey guys I need can someone me help get started on these two word problems.

An archway over a road is modeled by the quadratic function y < -.1x^2+12.

Can a car 6 feet wide and 7 feet high fit under the arch without crossing the median line?

You have 80 feet of fence to enclose a rectangular garden, The function a = 40x-x^2 gives you the area of the garden in sqft where x is the width. What width gives you the maximum gardening area? what is the maximum area?

Thanks.