Quadratic Functions, I can't get past the factoring part please help Use the function f(x) to answer the questions:

f(x) = 4x^2 − 7x − 15

Part A: What are the x-intercepts of the graph of f(x)? Show your work.

Part B: Is the vertex of the graph of f(x) going to be a maximum or a minimum? What are the coordinates of the vertex? Justify your answers and show your work.

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.

Please show your work, If you can only answer the first one that fine but please explain very clearly