garislurus 3x +4y+k=0 akan menyinggung lingkaran x^2+y^2+6X+8y=0jika k bernilai ......

Lingkaran

x² + y² + 6x + 8y = 0
(x + 3)² + (y + 4)² = 3² + 4² = 25
P(-3,-4)
r = √25 = 5

garis : 3x + 4y + k
r = 5
|-3 . 3 + -4 . 4 + k| / √(3² + 4²)
(25 + k)/5 = 5
25 + k = 25
k = 0