X - Vertex
[tex]Vertex = -\frac{b}{2a} \\Vertex = -\frac{16}{2(-2)} \\Vertex = -\frac{16}{-4} \\Vertex = 4[/tex]
Y - Vertex
[tex]y = -2x^{2} + 16x - 15 \\y = -2(4)^{2} + 16(4) - 15 \\y = -2(16) + 64 - 15 \\y = -32 + 64 - 15 \\y = 32 - 15 \\y = 17[/tex]
Vertex:(4, 17)