An expression is shown below: f(x) = 4x2 − 7x − 15 part a: what are the x-intercepts of the graph of f(x)? show your work. (2 points) part b: is the vertex of the graph of f(x) going to be a maximum or minimum? what are the coordinates of the vertex? justify your answers and show your work. (3 points) part c: what are the steps you would use to graph f(x)? justify that you can use the answers obtained in part a and part b to draw the graph. (5 points)