What is the vertex of the quadratic function: y=-3(x+5)^2-4

 V=(-5,-4) 
to find the vertex you use V=-b/2a
y=-3(x+5)^2-4
which then turns to 
y=-3x^2-30x-79
a=-3
b=-30                   x=30/2(-3)
                             x=30/-6
                              x=-5
plug x into the equation and solve for y =-3(-5)^2-30(-5)-79
                                                             y=-4
     x=-5 y=-4  Vertex=(-5,-4)