Find the vertex of the parabola y=x2−20x+10y = x^2 - 20x + 10y=x2−20x+10.
(9, −90)(9,\ -90)(9, −90)
(−10, −90)(-10,\ -90)(−10, −90)
(10, −90)(10,\ -90)(10, −90)
(11, −91)(11,\ -91)(11, −91)