Find the vertex of the function y = –x2 + 2x + 8.

it shows me different points as the answer.
Im not sure how to find that point. Here are the points: (1,7) or (1,9) or (4,-2) or (-1,-9)

Answered in a previous post. Here it is again:

Here's a quick way to find the vertex.

Use the format: [-b/2a, (4ac-b^2)/4a]

a = -1, b = 2, and c = 8

Substitute the values to find (x, y).

This will be your vertex.