1) If A=[5,3], B=[3,-2] and a point P is such that the area of the triangle PAB is 9, then the locus of P represents. A) a circle B) a pair of coincident lines C) a pair of parallel lines D) a pair of perpendicular lines Answer: Option CExplanation:Let P(x,y), A=(5,3),B=(3,-2) Area of △PAB= 12[xy15313−21] ⇒ 9=12|x(3+2)−y(5−3)+(−10−9)| ⇒ 18=|5x−2y−19| ⇒ 5x−2y−16=|18| ⇒ 5x−2y−19=±18 ⇒ 5x−2y=19±18 ⇒ 5x−2y=1 or 5x−2y=37 Which represents a pair of parallel lines