a = -2 (slider from -20 to 20, step 0.5)
b = 3 (slider from -20 to 20, step 0.5)
c = 4 (slider from -20 to 20, step 0.5)
f(x) = (a * x^(2)) + (b * x) + c
g(x) = (c * x^(2)) + (b * x) + a
d = IntegralBetween(f, g, -1, 1)