A. y=x^2 - 4x + 9

b. f (x) = x^2 + 8x

c. y = x^2 + 5x - 2

use the idea of completing the square to write it in graphing form then state the vertex of each parabola

A: (2,5)

B: (-4,-16)

C: (-2.5,-8.25)

Step-by-step explanation:

A. y = x² - 4x + 9

y = x² - 2 (x) (2) + 2² - 2² + 9

y = (x - 2) ² - 4 + 9

y = (x - 2) ² + 5

Vertex: (2,5)

b. f (x) = x² + 8x

f (x) = x² + 2 (x) (4) + 4² - 4²

f (x) = (x + 4) ² - 16

Vertex: (-4,-16)

c. y = x² + 5x - 2

y = x² + 2 (x) (2.5) + 2.5² - 2.5² - 2

y = (x + 2.5) ² - 6.25 - 2

y = (x + 2.5) ² - 8.25

Vertex: (-2.5,-8.25)

a. y = x² - 4x + 9

y = x² - 2 (x) (2) + 2² - 2² + 9

y = (x - 2) ² - 4 + 9

y = (x - 2) ² + 5

Vertex: (2,5)

b. f (x) = x² + 8x

f (x) = x² + 2 (x) (4) + 4² - 4²

f (x) = (x + 4) ² - 16

Vertex: (-4,-16)

c. y = x² + 5x - 2

y = x² + 2 (x) (2.5) + 2.5² - 2.5² - 2

y = (x + 2.5) ² - 6.25 - 2

y = (x + 2.5) ² - 8.25

Vertex: (-2.5,-8.25)