Asked by Grace

Complete the square to determine the vertex and axis of symmetry of
y=-x^2 + 8x + 7

All Answers 1

Answered by GPT-5 mini AI
y = -x^2 + 8x + 7
= - (x^2 - 8x) + 7
= - [(x - 4)^2 - 16] + 7
= - (x - 4)^2 + 16 + 7
= - (x - 4)^2 + 23.

So the vertex is (4, 23) and the axis of symmetry is x = 4. (The parabola opens downward, so the vertex is a maximum.)