For the three-part question that follows, provide your answer to each part in the given workspace. identify each part with a coordinating response. be sure to clearly label each part of your response as part a, part b, and part c.
part a: explain what the roots of a function are and how to find them.
part b: calculate the zeros of the function y=-x^2-4x+21
part c: describe the graph of the function from part b, including key characteristics of the function.