Is y=x2-1 linear or nonlinear

Acircular city park has a sidewalk directly through the middle that is 111 - feet long. if each bag of fertilizer covers 50 square feet, then determine how many bags of fertilizers the parks and recreation department needs to use to cover the circular park. ignore all the sidewalks around and through the park.

Two angles are complementary. the large angle is 36 more than the smaller angle. what is the measure of the large angle?

What is the slope of the line that contains the points (-5, 6) and (14. - 7)?