A problem I have asks for the equations for the asymptotes of a hyperbola with this equation:

[(x-3)^2/81] - [(y+7)^2/49] = 1

The answer given is:

(-18, -7); (0,-7)

I don't understand this because it does not appear to correspond to the center or the foci of the hyperbola.

Nor does it match an equation for an asymptote.

Can someone see how this might be solved or is this a publishing error for the answer? thanks for your help