(a)[4]
Find the equation of the tangent to the circle at the point $(2, 8)$, giving your answer in the form $ax + by + c = 0$.
(b)[5]
Because the line $x + 3y = k$ does not intersect the circle, show that $k^2 - 20k - 220 > 0$.
Mathematics 9709 · AS & A Level · Coordinate geometry
Coordinate geometry — practice question
A circle is described by $x^2 + y^2 + 4x - 8y - 12 = 0$.