Question

Which equation is y = 9x2 + 9x – 1 rewritten in vertex form?

Answer 1

Vertex for X
$-\frac{9}{2(9)} = -\frac{2}{18} = -\frac{1}{9}$

Vertex for Y
$y = 9x^{2} + 9x - 1 \\y = 9(-\frac{1}{9})^{2} + 9(-\frac{1}{9}) - 1 \\y = 9(\frac{1}{81}) - 1 - 1 \\y = \frac{1}{9} - 1 - 1 \\y = -\frac{8}{9} - 1 \\y = -1\frac{8}{9}$

Vertex
(h, k) = (⁻¹/₉, -1⁸/₉)