Find the vertex of the parabola x2−4x−8y+20=0x^2 - 4x - 8y + 20 = 0x2−4x−8y+20=0.
(0,0)(0, 0)(0,0)
−2,2-2, 2−2,2
(2,−2)(2, -2)(2,−2)
(2,2)(2, 2)(2,2)