What is the vertex and the equation of the axis of symmetry of the graph of y is equal to x squared minus 6 x minus 7 ?
A
vertex: open paren 20 comma negative 3 close paren a.o.s: x is equal to 20B
vertex: open paren 3 comma negative 16 close paren a.o.s: x is equal to 3C
vertex: open paren negative 3 comma 20 close paren a.o.s: x is equal to negative 3D
vertex: open paren negative 16 comma 3 close paren a.o.s: x is equal to negative 16