persamaan garis singgung lingkaran yang berpusat di (-2,-1) dan jari jari 5 di titik (2,-4) adalah ... tolong penting

Pusat (a,b) = (-2,-1), r = 5
(x - a)^2 + (y - b)^2 = r^2
(x + 2)^2 + (y + 1)^2 = 5^2
Persamaan garis singgung di (2,-4) = (x1, y1)
(x1 + 2)(x + 2) + (y1 + 1)(y + 1) = 5^2
(2 + 2)(x + 2) + (-4 + 1)(y + 1) = 25
4x + 8 - 3y - 3 = 25
4x - 3y = 20

4x - 3y - 20 = 0

(x-a) (x₁-a) + (y-b) (y₁-b)= r²
(x+2) (2+2) + (y+1) (-4+1) = 5²
4 (x+2) - 3 (y+1) = 25
4x + 8 -3y -3 = 25
-3y = -4x + 25 - 8 + 3
3y = 4x - 25 +5
3y = 4x - 20

[tex]y = \frac{4x-20}{3} [/tex]