If Q is the foot of the perpendicular of the point P(3, 6) on the line x - 2y + 4 = 0, then the equation of PQ is
2x + y = 12
PQ is r to x - 2y + 4
⇒ slope of PQ = -2
P(3,6) is a point on PQ and its slope is -2
⇒ equation of PQ ≡ Y - 6 = -2(X - 3)
⇒ Y - 6 = -2x + 6
⇒ 2x + y = 12