Jawabanmu

2014-06-08T14:46:50+07:00
(x₁, y₁) = (7, 1)

x² + y² - 6x + 4y - 12 = 0  ⇒ A = -6  B = 4  C = -12
x₁x + y₁y + A ( \frac{ x_{1}+x }{2} ) + B( \frac{ y_{1}+y }{2}) + C = 0
(7)x + (1)y - 6( \frac{7+x}{2}) + 4( \frac{1+ y }{2}) - 12 = 0
14x + y - 42 - 6x + 4 + 4y - 12 = 0
8x + 5y - 52 = 0