3x + y = 0 A(2, -1) B(4, 3)
m_AB = (3 + 1) / (4 – 2) = 4 / 2 = 2
m_⊥ = -1 / 2
x_H = (2 + 4) / 2 = 6 / 2 = 3
y_H = (3 – 1) / 2 = 2 / 2 = 1
y – 1 = -1 / 2 (x – 3)
y – 1 = -1 / 2 x + 3 / 2
1 / 2 x + y – 1 – 3 / 2 = 0
1 / 2 x + y – 2 / 2 – 3 / 2 = 0
1 / 2 x + y – 5 / 2 = 0
x + 2y - 5 = 0 { x + 2y - 5 = 0 3x + y = 0 } { x + 2y - 5 = 0 y = -3x } { x + 2(-3x) - 5 = 0 y = -3x } { x - 6x - 5 = 0 y = -3x } { -5x - 5 = 0 y = -3x } { -5x = 5 y = -3x } { x = -1 y = -3(-1) } C(-1; 3)