Answer:
max = 150
Explanation:
the maximum height is the value of the y- coordinate of the vertex.
given a quadratic equation in standard form : y = ax² + bx + c = 0 ( a ≠ 0 )
then the x- coordinate of the vertex is
x = -

- 16x² + 64x + 86 = 0 ← is in standard form
with a = - 16 and b = 64 , then
= -
= 2
substitute x = 2 into the quadratic for corresponding y- coordinate
- 16(2)² + 64(2) + 86 = - 16(4) + 128 + 86 = - 64 + 128 + 86 = 150
vertex = (2, 150 )
then maximum height is 150 units