Tolong sama caranya ya kak Materi persamaan garis singgung lingkaran

mencari gradien (m) :
2x+y+3 = 0
y = -2x - 3
m = -2

mencari titik pusat (M)
M = (- A/2 , - B/2)
= (- 2/2 , - (-4)/2)
= (-1 , 2) ---> (a,b)

mencari jari-jari
r = √ A²/4 + B²/4 - C
= √ 2²/4 + (-4)²/4 - (-15)
= √ 4/4 + 16/4 + 15
= √ 1 + 4+ 15
= √20
= 2√5

mencari garis singgung

y-b = m (x-a) ± r √1 +m²
y-2 = -2 (x- (-1)) ± 2√5.√1+(-2)²
y-2 = -2x-2 ±2√5 . √5
y-2 = -2x-2 ±2.5
y-2 = -2x-2 ± 10

garis 1
y-2 = -2x-2+10
y = -2x-2+10+2
y = -2x + 10
2x + y - 10 = 0

garis 2
y-2 =-2x-2-10
y = -2x -2-10+2
y = -2x - 10
2x + y + 10 = 0 (A)