a_1 = 0.8 (slider from -5 to 5, step 0.1)
b_1 = -3.9 (slider from -5 to 5, step 0.1)
c_1 = 4.2 (slider from -5 to 5, step 0.1)
f(x) = a_1 * x^(2.0) + b_1 * x + c_1
A, B = Root(f(x))