Is the quadratic equation x^2 - 2x - 3 = 0

Question

a parabola or two vertical lines when graphed?

Answer 1

since it is (x-3)(x+1) you know you have two roots. No straight line will cut the x-axis in more than one place (except y=0).

And since the coefficient of x^2 is nonzero, you know that it is in fact a parabola. I can't think of any quadratic that graphs to two lines.