Question

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​

Answer 1

A: (2,5)

B: (-4,-16)

C: (-2.5,-8.25)

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)

Answer 2

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)