Formes polynomes degré 2

a = 0.5 (slider from -5 to 5)
c = -2.9 (slider from -5 to 5)
x_1 = -0.2 (slider from -5 to 5)
x_2 = 2.8 (slider from -5 to 5)
f(x) = (a * x^(2))
g(x) = (a * x^(2)) + c
h(x) = ((a * (x - x_1)) * (x - x_2))