The equation of a circle is (x - a) ^ 2 + (y - 3) ^ 2 = 20 The line y = 1/2 * x + 6 is a tangent to the circle at thepoint P. (a) Show that one possible value of a is 4 and find the other possible value. (b) For a = 4 , find the equation of the normal to the circle at P (c) For a = 4 find the equations of the two tangents to the circle which are parallel to the normalfound in (b).​