I'm not fluent in English, so I can't reslove this kata.
Translated by Google Translate.
:(

Disregard the number inside the parentheses in front of the variable x in the vertex form and I got, erroneously, 100% correct.
example "2(9x + 14)2 + 5" ==> a = 2, h = -14 and k = 5. The correct answer is Xv = -14/9 = 1.55555555556 and not Xv = -14.

fixed!

I did several Random Tests and usually it fails between 10 and 15 cases. In all failure cases it did not check the x coordinate values of the vertex.
Examples:
(1.8888888888888888, 9.0) should equal (17.0, 9.0).
(1.0, -12.0) should equal (6.0, -12.0).
(3.5, 7.0) should equal (7.0, 7.0).
(-3.75, -9.0) should equal (-15.0, -9.0).
(-0.5555555555555556, 15.0) should equal (-5.0, 15.0).
(-1.8571428571428572, 17.0) should equal (-13.0, 17.0).
(-8.5, -2.0) should equal (-17.0, -2.0).

EDITS 1, 2, 3: layout.
EDIT 4: I believe the error must be in the vertex form = a(x - h)2 + k, specifically in case there is a number in front of the variable x (inside the parentheses).
example "2(9x + 14)2 + 5" ==> a = 2, h = -14 and k = 5. But what about the 9 that comes with x? Normally the vertex form doesn't have the coefficient in front of the x , otherwise the "h" should be divided by it.

https://www.geogebra.org/calculator/p27h3w5g ==> graphic ==> 7(6x + 6)2 + 18

*pt-br: Eu sou professor de matemática e percebi que algumas respostas não batem.
ex: f(x) ="7(6x + 6)2 + 18" ==> V(-1.0, 18.0) valores corretos.
f(x) = "x2 - x - 9" ==> V(0.5, -9.25) valores corretos.
isso só nos testes básicos

en: I'm a math teacher and I perceived that some answers don't match. (google translate)
ex: f(x) ="7(6x + 6)2 + 18" ==> V(-1.0, 18.0) correct values.
f(x) = "x2 - x - 9" ==> V(0.5, -9.25) correct values.
this is only in the basic tests