What are the vertex and x-intercepts of the graph of y=x^2-4x-21?

Intercepts at (0,7) and (0,03)

Vertex at (2,-25)

Step-by-step explanation:

Axis of symmetry is - b/2a = - (-4) / 2 (1) = 4/2 = 2 x=2

Plug x=2 into the equation and get 2^2-4 (2) - 21 = 4-8-21 = - 25

Vertex is (2,-25)

Factor the equation (x-7) (x+3)

Set x-7=0, x=7

set x+3=0, x = - 3

x intercepts at 7 and - 3