Forme 1 : ax^2+bx+c

Forme 2 : a(x-α)^2+β

Forme3 :  a(x-x1)(x-x2)

a = -5 (slider from -5 to 5, step 0.1)
b = -1.2 (slider from -5 to 5, step 0.1)
c = -3.1 (slider from -5 to 5, step 0.1)
α = 2.9 (slider from -5 to 5, step 0.1)
β = -5 (slider from -5 to 5, step 0.1)
x1 = -5 (slider from -5 to 5, step 0.1)
x2 = -5 (slider from -5 to 5, step 0.1)
f1(x) = a * x * x + b * x + c
f2(x) = a * (x - α)^(2) + β
f3(x) = a * (x - x1) * (x - x2)
d = false
e = false
f = false