A parabola has a y-intercept of 5 and contains the points (2,-3) and (-1, 12). What are the coordinates of the vertex?
Use any method you like but you must show ALL of your work and justify your answer.
Hint: You could use the equation of a parabola = 2 + + to create a system of linear equations from the given points. We learned how to solve a system of linear equations in Chapter 1. Once you have the quadratic equation, you can use any method you choose to find the vertex given the standard form.