Α = (1.84, 5.1)
Β = (4.14, 3.9)
Γ = (5.98, 5.54)
a = 1.3 (slider from -5 to 5, step 0.1)
b = -2.5 (slider from -5 to 5, step 0.1)
c = 0.9 (slider from -5 to 5, step 0.1)
d: y = a * (x - 1)^(2) + b x + c
Δ = Extremum(a * (x - 1)^(2) + b * x + c)