I’ve two question please help me to solve.

1. The line y = 0 is a tangent to the circle (x - 8)^2 + (y - a)^2 = 16. Find the value of a.

2. The circle, center (p, q) radius 25, meets the x-axis at (-7, 0) and (7, 0), where q > 0.

a) Find the value of p and q.

b) Find the coordinates of the points where the circle meets the y-axis.