In[]:=
a=Input["a"];b=Input["b"];c=Input["c"];d=((b)^2-4*a*c);StringForm["a = ``, b = ``, c = ``.",a,b,c]StringForm["Discriminant = ``.",d]f=(-b-Sqrt[(d)])/(2*a);g=(-b+Sqrt[(d)])/(2*a);StringForm["x= `` or x= ``.",f,g]If[d==0,f=0,f=f];Plot[a*x^2+b*x+c,{x,f,g}]