Vertex Form: y = a(x-h)² + k
Vertex: (h, k)
h = -b/2a
k = 4ac - b² or k = f(h), therefore solve for h first.
4a
y = -2x² + 8x + 7, where a = -2 b = 8 c = 7
h = -(8)
2 (-2)
h = -8/-2
h = 2
k = f(h)
f(4) = -2x² + 8x + 7
= -2 (2)² + 8 (2) + 7
= -2(4) + 16 + 7
= - 8 + 23
k = 15
y = a (x-h)² + k
a = -2 h = 2 k = 15
Vertex Form of the function y = -2x² + 8x + 7:
y = -2 (x - 2)² + 15