Question

What is the vertex of this equation?

y=-x^2+10x-21

(5, 4)

(1, -9)

(-4, -2)

(7, -3)

Answer 1

(5, 4)

Explanation:

The equation can be written in vertex form by adding and subtracting 25:

y = -(x^2 -10x +25) -21 +25

y = -(x -5)^2 +4

Then the vertex can be identified as (5, 4).