Try varying the values of a, b and c!

a = -0.5 (slider from -5 to 5, step 0.1)
b = 1.7 (slider from -5 to 5, step 0.1)
c = 3.7 (slider from -5 to 5, step 0.1)
f(x) = a * x^(2.0) + b * x + c
d: b^(2.0) - 4.0 * a * c
text1: "The discriminant is " + d + "."
v: -(b) / (2.0 * a)
text2: "The vertex is (" + v + ", " + (f(v)) + ")."
A: (v, f(v))
text3: "The axis of symmetry is x = " + v + "."
e: x = v