print("For y= ax^2+bx+c, input a") a = tonumber(io.read())
print("For y= ax^2+bx+c, input b") b = tonumber(io.read())
print("For y= ax^2+bx+c, input c") c = tonumber(io.read())
print("For y= ax^2+bx+c, input y") y = tonumber(io.read())

C = c - y
D = b*b - 4*a*C

if D < 0 then
    print("no real solution")
elseif D == 0 then
    print("one real solution")
    print(-b/(2*a))
else
    print("two real solutions")
    print((-b+math.sqrt(D))/2/a)
    print((-b-math.sqrt(D))/2/a)
end