Chapter 13, Problem 13.21PE

(Algebra: vertex form equations) The equation of a parabola can be expressed in either standard form (y = ax² + bx + c) or vertex form (y = a(x – h)² + k). Write a program that prompts the user to enter a, b, and c as integers in standard form and display $h\left(=\frac{b}{2a}\right)$ and $k\left(=\frac{4ac-b^2}{4a}\right)$ in the vertex form. Display h and k as rational numbers. Here are some sample runs:

Enter a, b, c: 1 3 1 h is –3/2 k is –5/4

Enter a, b, c: 2 3 4 h is –3/4 k is 23/8