Given f(x)=x2−4xf(x) = x^2 - 4xf(x)=x2−4x, what is the vertex of the parabola?
(0,−4)(0, -4)(0,−4)
(4,0)(4, 0)(4,0)
(2,−4)(2, -4)(2,−4)
(−2,4)(-2, 4)(−2,4)