a = -0.9 (slider from -5 to 5, step 0.01)
b = 5 (slider from -5 to 5, step 0.1)
c = 1.4 (slider from -10 to 10, step 0.1)
f(x) = a * x^(2) + b * x + c
g(x) = 2 * x^(2)
h(x) = a * x + b