f(x)=a*x^2+b*x+c

Bài học: Vẽ đồ thị

a = -1.4 (slider from -5 to 5, step 0.1)
b = 5 (slider from -5 to 5, step 0.1)
c = 0.20000000000000018 (slider from -5 to 5, step 0.1)
f(x) = a x² + b x + c