Hi there, stuck on a tangent question.

a. Show that the point P(5,10) lies on the circle with equation (x+1)^2 + (y-2)^2 = 100.

b. PQ is a diameter of this circle as shown in the diagram. Find the equation of the tangent at Q.

I can do part a, and know how to find the equation of a tangent, but I don't know how to get the coordinates of Q so I can solve the equation.

Thanks in advance