What are the vertex and x-intercepts of the graph of the function below?

y = x^2 - 6x-7

A. Vertex: (3,-16); Intercepts: x = 1, - 7

B. Vertex: (3, - 16); Intercepts: x=-1,7

C. Vertex: (3,-2); Intercepts: x = - 1,7

D. Vertex: (3,-2); Intercepts: x = 1, - 7

y = x^2 - 6x-7

Vertex = - b / 2a

b = - 6

a = 1

- (-6) / 2 (1) = 3

x = 3

Use the substitution method to find y

y = (3) ^2-6 (3) - 7

(3) (3) - 18-7

9-25

y = - 16

Vertex is (3, 16)

Find x - intercept (y = 0)

y = x^2 - 6x-7

(x-7) (x+1)

x-7 = 0

Move - 7 to the other side. Sign changes from - 7 to 7

x-7+7 = 0+7

x = 7

x+1 = 0

Move + 1 to the other side. Sign changes from + 1 to - 1

x+1-1 = 0-1

x = - 1

Answer : B. Vertex: (3, - 16); Intercepts: x=-1,7